XR device and method for controlling the same

ABSTRACT

Disclosed are an extended reality (XR) device and a control method thereof, which are applicable to all of 5G communication technology field, a robot technology field, an autonomous driving technology field, and an AI technology field.

This application claims the benefit of Korean Patent Application No.10-2019-0103528, filed on Aug. 23, 2019, which is hereby incorporated byreference as if fully set forth herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to an extended reality (XR) device forproviding augmented reality (AR) mode and virtual reality (VR) mode anda method of controlling the same. More particularly, the presentdisclosure is applicable to all of the technical fields of 5^(th)generation (5G) communication, robots, self-driving, and artificialintelligence (AI).

Discussion of the Related Art

VR (Virtual Reality) technology provides real world objects andbackgrounds only with CG (Computer Graphic) image. AR (AugmentedReality) technology provides a CG image created virtually on a realobject image. MR (Mixed) technology is a computer graphics technologythat mixes and combines virtual objects with the real world. Theabove-described VR, AR, MR, etc. are also referred to simply as extendedreality (XR) technology.

Specifically, Augmented Reality (AR)—based devices may recognize a realspace and a real object in three dimensions (3D) through a camera, andmay display the real space and a virtual object on a display screen.However, a conventional device according to the related art hasdisadvantages in that such a virtual object is movable only based on auser touch recognized on the screen.

On the other hand, the screen of the AR device has been designed in twodimensions (2D), and a touch sensor has also been designed to recognizeonly 2D coordinates of a target object, so that it is impossible toadjust a depth value of the virtual object.

SUMMARY OF THE INVENTION

Accordingly, the present disclosure is directed to an XR device and amethod for controlling the same that substantially obviate one or moreproblems due to limitations and disadvantages of the related art.

An object of the present disclosure is to provide an XR device providedwith two cameras operating in different ways, such thatthree-dimensional (3D) effects can be added to an in-screen virtualobject of the XR device.

Another object of the present disclosure is to provide a solution forallowing a plurality of virtual objects to be simultaneously selectedwithin a minimum period of time.

Another object of the present disclosure is to provide an XR device foranalyzing history information so as to adaptively change a groupingprocess needed for depth adjustment of the virtual objects.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, amethod for controlling an XR device provided with a plurality of camerasincludes capturing at least one real object located in a first directionthrough a first camera, displaying at least one virtual object and theat least one captured real object, wherein the displayed virtual objectis changed based on the captured real object, in response to a firsttouch command recognized through a screen of the XR device, moving theat least one virtual object to a first position (i.e., a first in-screenposition) contained in the screen, wherein the virtual object remainsunchanged in size, capturing a user who is located in a second directionthrough a second camera, wherein the first direction and the seconddirection are different from each other, and in response to a secondtouch command recognized through the screen of the XR device and amotion of the user who is spaced apart from the screen of the XR device,moving the at least one virtual object to a second position (i.e., asecond in-screen position) contained in the screen, wherein the virtualobject is changed in size.

In accordance with another aspect of the present disclosure, an extendedreality (XR) device provided with a plurality of cameras includes afirst camera configured to capture at least one real object located in afirst direction, a display module configured to display at least onevirtual object and the at least one captured real object, wherein thedisplayed virtual object is changed based on the captured real object, acontroller, in response to a first touch command recognized through ascreen of the XR device, configured to move the at least one virtualobject to a first position (i.e., a first in-screen position) containedin the screen, wherein the virtual object remains unchanged in size, anda second camera configured to capture a user who is located in a seconddirection, wherein the first direction and the second direction aredifferent from each other. The controller, in response to a second touchcommand recognized through the screen of the XR device and a motion ofthe user who is spaced apart from the screen of the XR device, may movethe at least one virtual object to a second position (i.e., a secondin-screen position) contained in the screen, wherein the virtual objectis changed in size.

It is to be understood that both the foregoing general description andthe following detailed description of the present disclosure areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a diagram illustrating an exemplary resource grid to whichphysical signals/channels are mapped in a 3^(rd) generation partnershipproject (3GPP) system;

FIG. 2 is a diagram illustrating an exemplary method of transmitting andreceiving 3GPP signals;

FIG. 3 is a diagram illustrating an exemplary structure of asynchronization signal block (SSB);

FIG. 4 is a diagram illustrating an exemplary random access procedure;

FIG. 5 is a diagram illustrating exemplary uplink (UL) transmissionbased on a UL grant;

FIG. 6 is a conceptual diagram illustrating exemplary physical channelprocessing;

FIG. 7 is a block diagram illustrating an exemplary transmitter andreceiver for hybrid beamforming;

FIG. 8(a) is a diagram illustrating an exemplary narrowband operation,and FIG. 8(b) is a diagram illustrating exemplary machine typecommunication (MTC) channel repetition with radio frequency (RF)retuning;

FIG. 9 is a block diagram illustrating an exemplary wirelesscommunication system to which proposed methods according to the presentdisclosure are applicable;

FIG. 10 is a block diagram illustrating an artificial intelligence (AI)device 100 according to an embodiment of the present disclosure;

FIG. 11 is a block diagram illustrating an AI server 200 according to anembodiment of the present disclosure;

FIG. 12 is a diagram illustrating an AI system 1 according to anembodiment of the present disclosure;

FIG. 13 is a block diagram illustrating an extended reality (XR) deviceaccording to embodiments of the present disclosure;

FIG. 14 is a detailed block diagram illustrating a memory illustrated inFIG. 13;

FIG. 15 is a block diagram illustrating a point cloud data processingsystem;

FIG. 16 is a block diagram illustrating a device including a learningprocessor;

FIG. 17 is a flowchart illustrating a process of providing an XR serviceby an XR device 1600 of the present disclosure, illustrated in FIG. 16;

FIG. 18 is a diagram illustrating the outer appearances of an XR deviceand a robot;

FIG. 19 is a flowchart illustrating a process of controlling a robot byusing an XR device;

FIG. 20 is a diagram illustrating a vehicle that provides a self-drivingservice;

FIG. 21 is a flowchart illustrating a process of providing an augmentedreality/virtual reality (AR/VR) service during a self-driving service inprogress;

FIG. 22 is a conceptual diagram illustrating an exemplary method forimplementing an XR device using an HMD type according to an embodimentof the present disclosure.

FIG. 23 is a conceptual diagram illustrating an exemplary method forimplementing an XR device using AR glasses according to an embodiment ofthe present disclosure.

FIG. 24 is a conceptual diagram illustrating a method for allowing an XRdevice to move a virtual object from one position to another positionaccording to the related art.

FIG. 25 is a conceptual diagram illustrating a method for allowing aplurality of cameras of the XR device to perform different functionsaccording to an embodiment of the present disclosure.

FIG. 26 is a flowchart illustrating a method for controlling the XRdevice according to an embodiment of the present disclosure.

FIG. 27 is a conceptual diagram illustrating a method for allowing theXR device to distinguish movement of a user and movement of the XRdevice from each other according to an embodiment of the presentdisclosure.

FIG. 28 is a conceptual diagram illustrating a method for allowing theXR device to distinguish movement of a user from movement of the XRdevice according to another embodiment of the present disclosure.

FIG. 29 is a conceptual diagram illustrating examples of an X-axis, aY-axis, and a Z-axis according to the present disclosure.

FIG. 30 is a conceptual diagram illustrating a situation in which the XRdevice simultaneously displays a real object and a virtual objectaccording to an embodiment of the present disclosure.

FIG. 31 is a conceptual diagram illustrating a situation in which the XRdevice adjusts the depth of the virtual object in response to a firstmotion of the user.

FIG. 32 is a conceptual diagram illustrating a situation in which the XRdevice adjusts the depth of the virtual object in response to a secondmotion of the user.

FIG. 33 is a conceptual diagram illustrating a situation in which the XRdevice selects a plurality of virtual objects each having a depth to beadjusted.

FIG. 34 is a conceptual diagram illustrating a database (DB) needed toadaptively group a plurality of virtual objects each having a depth tobe adjusted based on AI.

FIGS. 35 and 36 are conceptual diagrams illustrating various situationsin which the XR device rotates the virtual object in response to changein the position of a user face.

FIG. 37 is a flowchart illustrating a method for allowing the XR deviceto communicate with a robot according to an embodiment of the presentdisclosure.

FIG. 38 is a view illustrating a screen image acquired when the XRdevice displays a virtual object corresponding to the robot based on theconcept of FIG. 37.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Reference will now be made in detail to embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts, and aredundant description will be avoided. The terms “module” and “unit” areinterchangeably used only for easiness of description and thus theyshould not be considered as having distinctive meanings or roles.Further, a detailed description of well-known technology will not begiven in describing embodiments of the present disclosure lest it shouldobscure the subject matter of the embodiments. The attached drawings areprovided to help the understanding of the embodiments of the presentdisclosure, not limiting the scope of the present disclosure. It is tobe understood that the present disclosure covers various modifications,equivalents, and/or alternatives falling within the scope and spirit ofthe present disclosure.

The following embodiments of the present disclosure are intended toembody the present disclosure, not limiting the scope of the presentdisclosure. What could easily be derived from the detailed descriptionof the present disclosure and the embodiments by a person skilled in theart is interpreted as falling within the scope of the presentdisclosure.

The above embodiments are therefore to be construed in all aspects asillustrative and not restrictive. The scope of the disclosure should bedetermined by the appended claims and their legal equivalents, not bythe above description, and all changes coming within the meaning andequivalency range of the appended claims are intended to be embracedtherein.

Introduction

In the disclosure, downlink (DL) refers to communication from a basestation (BS) to a user equipment (UE), and uplink (UL) refers tocommunication from the UE to the BS. On DL, a transmitter may be a partof the BS and a receiver may be a part of the UE, whereas on UL, atransmitter may be a part of the UE and a receiver may be a part of theBS. A UE may be referred to as a first communication device, and a BSmay be referred to as a second communication device in the presentdisclosure. The term BS may be replaced with fixed station, Node B,evolved Node B (eNB), next generation Node B (gNB), base transceiversystem (BTS), access point (AP), network or 5^(th) generation (5G)network node, artificial intelligence (AI) system, road side unit (RSU),robot, augmented reality/virtual reality (AR/VR) system, and so on. Theterm UE may be replaced with terminal, mobile station (MS), userterminal (UT), mobile subscriber station (MSS), subscriber station (SS),advanced mobile station (AMS), wireless terminal (WT), device-to-device(D2D) device, vehicle, robot, AI device (or module), AR/VR device (ormodule), and so on.

The following technology may be used in various wireless access systemsincluding code division multiple access (CDMA), frequency divisionmultiple access (FDMA), time division multiple access (TDMA), orthogonalfrequency division multiple access (OFDMA), and single carrier FDMA(SC-FDMA).

For the convenience of description, the present disclosure is describedin the context of a 3^(rd) generation partnership project (3GPP)communication system (e.g., long term evolution-advanced (LTE-A) and newradio or new radio access technology (NR)), which should not beconstrued as limiting the present disclosure. For reference, 3GPP LTE ispart of evolved universal mobile telecommunications system (E-UMTS)using evolved UMTS terrestrial radio access (E-UTRA), and LTE-A/LTE-Apro is an evolution of 3GPP LTE. 3GPP NR is an evolution of3GPP/LTE-A/LTE-A pro.

In the present disclosure, a node refers to a fixed point capable oftransmitting/receiving wireless signals by communicating with a UE.Various types of BSs may be used as nodes irrespective of their names.For example, any of a BS, an NB, an eNB, a pico-cell eNB (PeNB), a homeeNB (HeNB), a relay, and a repeater may be a node. At least one antennais installed in one node. The antenna may refer to a physical antenna,an antenna port, a virtual antenna, or an antenna group. A node is alsoreferred to as a point.

In the present disclosure, a cell may refer to a certain geographicalarea or radio resources, in which one or more nodes provide acommunication service. A “cell” as a geographical area may be understoodas coverage in which a service may be provided in a carrier, while a“cell” as radio resources is associated with the size of a frequencyconfigured in the carrier, that is, a bandwidth (BW). Because a range inwhich a node may transmit a valid signal, that is, DL coverage and arange in which the node may receive a valid signal from a UE, that is,UL coverage depend on a carrier carrying the signals, and thus thecoverage of the node is associated with the “cell” coverage of radioresources used by the node. Accordingly, the term “cell” may mean theservice overage of a node, radio resources, or a range in which a signalreaches with a valid strength in the radio resources, undercircumstances.

In the present disclosure, communication with a specific cell may amountto communication with a BS or node that provides a communication serviceto the specific cell. Further, a DL/UL signal of a specific cell means aDL/UL signal from/to a BS or node that provides a communication serviceto the specific cell. Particularly, a cell that provides a UL/DLcommunication service to a UE is called a serving cell for the UE.Further, the channel state/quality of a specific cell refers to thechannel state/quality of a channel or a communication link establishedbetween a UE and a BS or node that provides a communication service tothe specific cell.

A “cell” associated with radio resources may be defined as a combinationof DL resources and UL resources, that is, a combination of a DLcomponent carrier (CC) and a UL CC. A cell may be configured with DLresources alone or both DL resources and UL resources in combination.When carrier aggregation (CA) is supported, linkage between the carrierfrequency of DL resources (or a DL CC) and the carrier frequency of ULresources (or a UL CC) may be indicated by system informationtransmitted in a corresponding cell. A carrier frequency may beidentical to or different from the center frequency of each cell or CC.Hereinbelow, a cell operating in a primary frequency is referred to as aprimary cell (Pcell) or PCC, and a cell operating in a secondaryfrequency is referred to as a secondary cell (Scell) or SCC. The Scellmay be configured after a UE and a BS perform a radio resource control(RRC) connection establishment procedure and thus an RRC connection isestablished between the UE and the BS, that is, the UE is RRC_CONNECTED.The RRC connection may mean a path in which the RRC of the UE mayexchange RRC messages with the RRC of the BS. The Scell may beconfigured to provide additional radio resources to the UE. The Scelland the Pcell may form a set of serving cells for the UE according tothe capabilities of the UE. Only one serving cell configured with aPcell exists for an RRC_CONNECTED UE which is not configured with CA ordoes not support CA.

A cell supports a unique radio access technology (RAT). For example, LTERAT-based transmission/reception is performed in an LTE cell, and 5GRAT-based transmission/reception is performed in a 5G cell.

CA aggregates a plurality of carriers each having a smaller system BWthan a target BW to support broadband. CA differs from OFDMA in that DLor UL communication is conducted in a plurality of carrier frequencieseach forming a system BW (or channel BW) in the former, and DL or ULcommunication is conducted by loading a basic frequency band dividedinto a plurality of orthogonal subcarriers in one carrier frequency inthe latter. In OFDMA or orthogonal frequency division multiplexing(OFDM), for example, one frequency band having a certain system BW isdivided into a plurality of subcarriers with a predetermined subcarrierspacing, information/data is mapped to the plurality of subcarriers, andthe frequency band in which the information/data has been mapped istransmitted in a carrier frequency of the frequency band throughfrequency upconversion. In wireless CA, frequency bands each having asystem BW and a carrier frequency may be used simultaneously forcommunication, and each frequency band used in CA may be divided into aplurality of subcarriers with a predetermined subcarrier spacing.

The 3GPP communication standards define DL physical channelscorresponding to resource elements (REs) conveying informationoriginated from upper layers of the physical layer (e.g., the mediumaccess control (MAC) layer, the radio link control (RLC) layer, thepacket data convergence protocol (PDCP) layer, the radio resourcecontrol (RRC) layer, the service data adaptation protocol (SDAP) layer,and the non-access stratum (NAS) layer), and DL physical signalscorresponding to REs which are used in the physical layer but do notdeliver information originated from the upper layers. For example,physical downlink shared channel (PDSCH), physical broadcast channel(PBCH), physical multicast channel (PMCH), physical control formatindicator channel (PCFICH), and physical downlink control channel(PDCCH) are defined as DL physical channels, and a reference signal (RS)and a synchronization signal are defined as DL physical signals. An RS,also called a pilot is a signal in a predefined special waveform knownto both a BS and a UE. For example, cell specific RS (CRS), UE-specificRS (UE-RS), positioning RS (PRS), channel state information RS (CSI-RS),and demodulation RS (DMRS) are defined as DL RSs. The 3GPP communicationstandards also define UL physical channels corresponding to REsconveying information originated from upper layers, and UL physicalsignals corresponding to REs which are used in the physical layer but donot carry information originated from the upper layers. For example,physical uplink shared channel (PUSCH), physical uplink control channel(PUCCH), and physical random access channel (PRACH) are defined as ULphysical channels, and DMRS for a UL control/data signal and soundingreference signal (SRS) used for UL channel measurement are defined.

In the present disclosure, physical shared channels (e.g., PUSCH andPDSCH) are used to deliver information originated from the upper layersof the physical layer (e.g., the MAC layer, the RLC layer, the PDCPlayer, the RRC layer, the SDAP layer, and the NAS layer).

In the present disclosure, an RS is a signal in a predefined specialwaveform known to both a BS and a UE. In a 3GPP communication system,for example, the CRS being a cell common RS, the UE-RS for demodulationof a physical channel of a specific UE, the CSI-RS used tomeasure/estimate a DL channel state, and the DMRS used to demodulate aphysical channel are defined as DL RSs, and the DMRS used fordemodulation of a UL control/data signal and the SRS used for UL channelstate measurement/estimation are defined as UL RSs.

In the present disclosure, a transport block (TB) is payload for thephysical layer. For example, data provided to the physical layer by anupper layer or the MAC layer is basically referred to as a TB. A UEwhich is a device including an AR/VR module (i.e., an AR/VR device) maytransmit a TB including AR/VR data to a wireless communication network(e.g., a 5G network) on a PUSCH. Further, the UE may receive a TBincluding AR/VR data of the 5G network or a TB including a response toAR/VR data transmitted by the UE from the wireless communicationnetwork.

In the present disclosure, hybrid automatic repeat and request (HARQ) isa kind of error control technique. An HARQ acknowledgement (HARQ-ACK)transmitted on DL is used for error control of UL data, and a HARQ-ACKtransmitted on UL is used for error control of DL data. A transmitterperforming an HARQ operation awaits reception of an ACK aftertransmitting data (e.g., a TB or a codeword). A receiver performing anHARQ operation transmits an ACK only when data has been successfullyreceived, and a negative ACK (NACK) when the received data has an error.Upon receipt of the ACK, the transmitter may transmit (new) data, andupon receipt of the NACK, the transmitter may retransmit the data.

In the present disclosure, CSI generically refers to informationrepresenting the quality of a radio channel (or link) establishedbetween a UE and an antenna port. The CSI may include at least one of achannel quality indicator (CQI), a precoding matrix indicator (PMI), aCSI-RS resource indicator (CRI), a synchronization signal block resourceindicator (SSBRI), a layer indicator (LI), a rank indicator (RI), or areference signal received power (RSRP).

In the present disclosure, frequency division multiplexing (FDM) istransmission/reception of signals/channels/users in different frequencyresources, and time division multiplexing (TDM) istransmission/reception of signals/channels/users in different timeresources.

In the present disclosure, frequency division duplex (FDD) is acommunication scheme in which UL communication is performed in a ULcarrier, and DL communication is performed in a DL carrier linked to theUL carrier, whereas time division duplex (TDD) is a communication schemein which UL communication and DL communication are performed in timedivision in the same carrier. In the present disclosure, half-duplex isa scheme in which a communication device operates on UL or UL only inone frequency at one time point, and on DL or UL in another frequency atanother time point. For example, when the communication device operatesin half-duplex, the communication device communicates in UL and DLfrequencies, wherein the communication device performs a UL transmissionin the UL frequency for a predetermined time, and retunes to the DLfrequency and performs a DL reception in the DL frequency for anotherpredetermined time, in time division, without simultaneously using theUL and DL frequencies.

FIG. 1 is a diagram illustrating an exemplary resource grid to whichphysical signals/channels are mapped in a 3GPP system.

Referring to FIG. 1, for each subcarrier spacing configuration andcarrier, a resource grid of N^(size,μ) _(grid)*N^(RB) _(sc) subcarriersby 14·2μ OFDM symbols is defined. Herein, N^(size,μ) _(grid) isindicated by RRC signaling from a BS, and μ represents a subcarrierspacing Δf given by Δf=2μ*15 [kHz] where μϵ{0, 1, 2, 3, 4} in a 5Gsystem.

N^(size,μ) _(grid) may be different between UL and DL as well as asubcarrier spacing configuration μ. For the subcarrier spacingconfiguration μ, an antenna port p, and a transmission direction (UL orDL), there is one resource grid. Each element of a resource grid for thesubcarrier spacing configuration μ and the antenna port p is referred toas an RE, uniquely identified by an index pair (k,l) where k is afrequency-domain index and l is the position of a symbol in a relativetime domain with respect to a reference point. A frequency unit used formapping physical channels to REs, resource block (RB) is defined by 12consecutive subcarriers (N^(RB) _(sc)=12) in the frequency domain.Considering that a UE may not support a wide BW supported by the 5Gsystem at one time, the UE may be configured to operate in a part(referred to as a bandwidth part (BWP)) of the frequency BW of a cell.

For the background technology, terminology, and abbreviations used inthe present disclosure, standard specifications published before thepresent disclosure may be referred to. For example, the followingdocuments may be referred to.

3GPP LTE

-   -   3GPP TS 36.211: Physical channels and modulation    -   3GPP TS 36.212: Multiplexing and channel coding    -   3GPP TS 36.213: Physical layer procedures    -   3GPP TS 36.214: Physical layer; Measurements    -   3GPP TS 36.300: Overall description    -   3GPP TS 36.304: User Equipment (UE) procedures in idle mode    -   3GPP TS 36.314: Layer 2—Measurements    -   3GPP TS 36.321: Medium Access Control (MAC) protocol    -   3GPP TS 36.322: Radio Link Control (RLC) protocol    -   3GPP TS 36.323: Packet Data Convergence Protocol (PDCP)    -   3GPP TS 36.331: Radio Resource Control (RRC) protocol    -   3GPP TS 23.303: Proximity-based services (Prose); Stage 2    -   3GPP TS 23.285: Architecture enhancements for V2X services    -   3GPP TS 23.401: General Packet Radio Service (GPRS) enhancements        for Evolved Universal Terrestrial Radio Access Network (E-UTRAN)        access    -   3GPP TS 23.402: Architecture enhancements for non-3GPP accesses    -   3GPP TS 23.286: Application layer support for V2X services;        Functional architecture and information flows    -   3GPP TS 24.301: Non-Access-Stratum (NAS) protocol for Evolved        Packet System (EPS); Stage 3    -   3GPP TS 24.302: Access to the 3GPP Evolved Packet Core (EPC) via        non-3GPP access networks; Stage 3    -   3GPP TS 24.334: Proximity-services (ProSe) User Equipment (UE)        to ProSe function protocol aspects; Stage 3    -   3GPP TS 24.386: User Equipment (UE) to V2X control function;        protocol aspects; Stage 3

3GPP NR (e.g. 5G)

-   -   3GPP TS 38.211: Physical channels and modulation    -   3GPP TS 38.212: Multiplexing and channel coding    -   3GPP TS 38.213: Physical layer procedures for control    -   3GPP TS 38.214: Physical layer procedures for data    -   3GPP TS 38.215: Physical layer measurements    -   3GPP TS 38.300: NR and NG-RAN Overall Description    -   3GPP TS 38.304: User Equipment (UE) procedures in idle mode and        in RRC inactive state    -   3GPP TS 38.321: Medium Access Control (MAC) protocol    -   3GPP TS 38.322: Radio Link Control (RLC) protocol    -   3GPP TS 38.323: Packet Data Convergence Protocol (PDCP)    -   3GPP TS 38.331: Radio Resource Control (RRC) protocol    -   3GPP TS 37.324: Service Data Adaptation Protocol (SDAP)    -   3GPP TS 37.340: Multi-connectivity; Overall description    -   3GPP TS 23.287: Application layer support for V2X services;        Functional architecture and information flows    -   3GPP TS 23.501: System Architecture for the 5G System    -   3GPP TS 23.502: Procedures for the 5G System    -   3GPP TS 23.503: Policy and Charging Control Framework for the 5G        System; Stage 2    -   3GPP TS 24.501: Non-Access-Stratum (NAS) protocol for 5G System        (5GS); Stage 3    -   3GPP TS 24.502: Access to the 3GPP 5G Core Network (5GCN) via        non-3GPP access networks    -   3GPP TS 24.526: User Equipment (UE) policies for 5G System        (5GS); Stage 3

FIG. 2 is a diagram illustrating an exemplary method oftransmitting/receiving 3GPP signals.

Referring to FIG. 2, when a UE is powered on or enters a new cell, theUE performs an initial cell search involving acquisition ofsynchronization with a BS (S201). For the initial cell search, the UEreceives a primary synchronization channel (P-SCH) and a secondarysynchronization channel (S-SCH), acquires synchronization with the BS,and obtains information such as a cell identifier (ID) from the P-SCHand the S-SCH. In the LTE system and the NR system, the P-SCH and theS-SCH are referred to as a primary synchronization signal (PSS) and asecondary synchronization signal (SSS), respectively. The initial cellsearch procedure will be described below in greater detail.

After the initial cell search, the UE may receive a PBCH from the BS andacquire broadcast information within a cell from the PBCH. During theinitial cell search, the UE may check a DL channel state by receiving aDL RS.

Upon completion of the initial cell search, the UE may acquire morespecific system information by receiving a PDCCH and receiving a PDSCHaccording to information carried on the PDCCH (S202).

When the UE initially accesses the BS or has no radio resources forsignal transmission, the UE may perform a random access procedure withthe BS (S203 to S206). For this purpose, the UE may transmit apredetermined sequence as a preamble on a PRACH (S203 and S205) andreceive a PDCCH, and a random access response (RAR) message in responseto the preamble on a PDSCH corresponding to the PDCCH (S204 and S206).If the random access procedure is contention-based, the UE mayadditionally perform a contention resolution procedure. The randomaccess procedure will be described below in greater detail.

After the above procedure, the UE may then perform PDCCH/PDSCH reception(S207) and PUSCH/PUCCH transmission (S208) in a general UL/DL signaltransmission procedure. Particularly, the UE receives DCI on a PDCCH.

The UE monitors a set of PDCCH candidates in monitoring occasionsconfigured for one or more control element sets (CORESETs) in a servingcell according to a corresponding search space configuration. The set ofPDCCH candidates to be monitored by the UE is defined from theperspective of search space sets. A search space set may be a commonsearch space set or a UE-specific search space set. A CORESET includes aset of (physical) RBs that last for a time duration of one to three OFDMsymbols. The network may configure a plurality of CORESETs for the UE.The UE monitors PDCCH candidates in one or more search space sets.Herein, monitoring is attempting to decode PDCCH candidate(s) in asearch space. When the UE succeeds in decoding one of the PDCCHcandidates in the search space, the UE determines that a PDCCH has beendetected from among the PDCCH candidates and performs PDSCH reception orPUSCH transmission based on DCI included in the detected PDCCH.

The PDCCH may be used to schedule DL transmissions on a PDSCH and ULtransmissions on a PUSCH. DCI in the PDCCH includes a DL assignment(i.e., a DL grant) including at least a modulation and coding format andresource allocation information for a DL shared channel, and a UL grantincluding a modulation and coding format and resource allocationinformation for a UL shared channel.

Initial Access (IA) Procedure

Synchronization Signal Block (SSB) Transmission and Related Operation

FIG. 3 is a diagram illustrating an exemplary SSB structure. The UE mayperform cell search, system information acquisition, beam alignment forinitial access, DL measurement, and so on, based on an SSB. The term SSBis interchangeably used with synchronization signal/physical broadcastchannel (SS/PBCH).

Referring to FIG. 3, an SSB includes a PSS, an SSS, and a PBCH. The SSBincludes four consecutive OFDM symbols, and the PSS, the PBCH, theSSS/PBCH, or the PBCH is transmitted in each of the OFDM symbols. ThePBCH is encoded/decoded based on a polar code and modulated/demodulatedin quadrature phase shift keying (QPSK). The PBCH in an OFDM symbolincludes data REs to which a complex modulated value of the PBCH ismapped and DMRS REs to which a DMRS for the PBCH is mapped. There arethree DMRS REs per RB in an OFDM symbol and three data REs between everytwo of the DMRS REs.

Cell Search

Cell search is a process of acquiring the time/frequency synchronizationof a cell and detecting the cell ID (e.g., physical cell ID (PCI)) ofthe cell by a UE. The PSS is used to detect a cell ID in a cell IDgroup, and the SSS is used to detect the cell ID group. The PBCH is usedfor SSB (time) index detection and half-frame detection.

In the 5G system, there are 336 cell ID groups each including 3 cellIDs. Therefore, a total of 1008 cell IDs are available. Informationabout a cell ID group to which the cell ID of a cell belongs isprovided/acquired by/from the SSS of the cell, and information about thecell ID among 336 cells within the cell ID is provided/acquired by/fromthe PSS.

The SSB is periodically transmitted with an SSB periodicity. The UEassumes a default SSB periodicity of 20 ms during initial cell search.After cell access, the SSB periodicity may be set to one of {5 ms, 10ms, 20 ms, 40 ms, 80 ms, 160 ms} by the network (e.g., a BS). An SSBburst set is configured at the start of an SSB period. The SSB burst setis composed of a 5-ms time window (i.e., half-frame), and the SSB may betransmitted up to L times within the SSB burst set. The maximum number Lof SSB transmissions may be given as follows according to the frequencyband of a carrier.

-   -   For frequency range up to 3 GHz, L=4    -   For frequency range from 3 GHz to 6 GHz, L=8    -   For frequency range from 6 GHz to 52.6 GHz, L=64

The possible time positions of SSBs in a half-frame are determined by asubcarrier spacing, and the periodicity of half-frames carrying SSBs isconfigured by the network. The time positions of SSB candidates areindexed as 0 to L−1 (SSB indexes) in a time order in an SSB burst set(i.e., half-frame). Other SSBs may be transmitted in different spatialdirections (by different beams spanning the coverage area of the cell)during the duration of a half-frame. Accordingly, an SSB index (SSBI)may be associated with a BS transmission (Tx) beam in the 5G system.

The UE may acquire DL synchronization by detecting an SSB. The UE mayidentify the structure of an SSB burst set based on a detected (time)SSBI and hence a symbol/slot/half-frame boundary. The number of aframe/half-frame to which the detected SSB belongs may be identified byusing system frame number (SFN) information and half-frame indicationinformation.

Specifically, the UE may acquire the 10-bit SFN of a frame carrying thePBCH from the PBCH. Subsequently, the UE may acquire 1-bit half-frameindication information. For example, when the UE detects a PBCH with ahalf-frame indication bit set to 0, the UE may determine that an SSB towhich the PBCH belongs is in the first half-frame of the frame. When theUE detects a PBCH with a half-frame indication bit set to 1, the UE maydetermine that an SSB to which the PBCH belongs is in the secondhalf-frame of the frame. Finally, the UE may acquire the SSBI of the SSBto which the PBCH belongs based on a DMRS sequence and PBCH payloaddelivered on the PBCH.

System Information (SI) Acquisition

SI is divided into a master information block (MIB) and a plurality ofsystem information blocks (SIBs). The SI except for the MIB may bereferred to as remaining minimum system information (RMSI). For details,the following may be referred to.

-   -   The MIB includes information/parameters for monitoring a PDCCH        that schedules a PDSCH carrying systemInformationBlock1 (SIB1),        and transmitted on a PBCH of an SSB by a BS. For example, a UE        may determine from the MIB whether there is any CORESET for a        Type0-PDCCH common search space. The Type0-PDCCH common search        space is a kind of PDCCH search space and used to transmit a        PDCCH that schedules an S1 message. In the presence of a        Type0-PDCCH common search space, the UE may determine (1) a        plurality of contiguous RBs and one or more consecutive symbols        included in a CORESET, and (ii) a PDCCH occasion (e.g., a        time-domain position at which a PDCCH is to be received), based        on information (e.g., pdcch-ConfigSIB1) included in the MM.    -   SIB1 includes information related to availability and scheduling        (e.g., a transmission period and an SI-window size) of the        remaining SIBs (hereinafter, referred to SIBx where x is an        integer equal to or larger than 2). For example, SIB1 may        indicate whether SIBx is broadcast periodically or in an        on-demand manner upon user request. If SIBx is provided in the        on-demand manner, SIB1 may include information required for the        UE to transmit an SI request. A PDCCH that schedules SIB1 is        transmitted in the Type0-PDCCH common search space, and SIB1 is        transmitted on a PDSCH indicated by the PDCCH.    -   SIBx is included in an SI message and transmitted on a PDSCH.        Each SI message is transmitted within a periodic time window        (i.e., SI-window).

Random Access Procedure

The random access procedure serves various purposes. For example, therandom access procedure may be used for network initial access,handover, and UE-triggered UL data transmission. The UE may acquire ULsynchronization and UL transmission resources in the random accessprocedure. The random access procedure may be contention-based orcontention-free.

FIG. 4 is a diagram illustrating an exemplary random access procedure.Particularly, FIG. 4 illustrates a contention-based random accessprocedure.

First, a UE may transmit a random access preamble as a first message(Msg1) of the random access procedure on a PRACH. In the presentdisclosure, a random access procedure and a random access preamble arealso referred to as a RACH procedure and a RACH preamble, respectively.

A plurality of preamble formats are defined by one or more RACH OFDMsymbols and different cyclic prefixes (CPs) (and/or guard times). A RACHconfiguration for a cell is included in system information of the celland provided to the UE. The RACH configuration includes informationabout a subcarrier spacing, available preambles, a preamble format, andso on for a PRACH. The RACH configuration includes associationinformation between SSBs and RACH (time-frequency) resources, that is,association information between SSBIs and RACH (time-frequency)resources. The SSBIs are associated with Tx beams of a BS, respectively.The UE transmits a RACH preamble in RACH time-frequency resourcesassociated with a detected or selected SSB. The BS may identify apreferred BS Tx beam of the UE based on time-frequency resources inwhich the RACH preamble has been detected.

An SSB threshold for RACH resource association may be configured by thenetwork, and a RACH preamble transmission (i.e., PRACH transmission) orretransmission is performed based on an SSB in which an RSRP satisfyingthe threshold has been measured. For example, the UE may select one ofSSB(s) satisfying the threshold and transmit or retransmit the RACHpreamble in RACH resources associated with the selected SSB.

Upon receipt of the RACH preamble from the UE, the BS transmits an RARmessage (a second message (Msg2)) to the UE. A PDCCH that schedules aPDSCH carrying the RAR message is cyclic redundancy check (CRC)-maskedby an RA radio network temporary identifier (RNTI) (RA-RNTI) andtransmitted. When the UE detects the PDCCH masked by the RA-RNTI, the UEmay receive the RAR message on the PDSCH scheduled by DCI delivered onthe PDCCH. The UE determines whether RAR information for the transmittedpreamble, that is, Msg1 is included in the RAR message. The UE maydetermine whether random access information for the transmitted Msg1 isincluded by checking the presence or absence of the RACH preamble ID ofthe transmitted preamble. If the UE fails to receive a response to Msg1,the UE may transmit the RACH preamble a predetermined number of or fewertimes, while performing power ramping. The UE calculates the PRACHtransmission power of a preamble retransmission based on the latestpathloss and a power ramping counter.

Upon receipt of the RAR information for the UE on the PDSCH, the UE mayacquire timing advance information for UL synchronization, an initial ULgrant, and a UE temporary cell RNTI (C-RNTI). The timing advanceinformation is used to control a UL signal transmission timing. Toenable better alignment between PUSCH/PUCCH transmission of the UE and asubframe timing at a network end, the network (e.g., BS) may measure thetime difference between PUSCH/PUCCH/SRS reception and a subframe andtransmit the timing advance information based on the measured timedifference. The UE may perform a UL transmission as a third message(Msg3) of the RACH procedure on a PUSCH. Msg3 may include an RRCconnection request and a UE ID. The network may transmit a fourthmessage (Msg4) in response to Msg3, and Msg4 may be treated as acontention solution message on DL. As the UE receives Msg4, the UE mayenter an RRC_CONNECTED state.

The contention-free RACH procedure may be used for handover of the UE toanother cell or BS or performed when requested by a BS command. Thecontention-free RACH procedure is basically similar to thecontention-based RACH procedure. However, compared to thecontention-based RACH procedure in which a preamble to be used israndomly selected among a plurality of RACH preambles, a preamble to beused by the UE (referred to as a dedicated RACH preamble) is allocatedto the UE by the BS in the contention-free RACH procedure. Informationabout the dedicated RACH preamble may be included in an RRC message(e.g., a handover command) or provided to the UE by a PDCCH order. Whenthe RACH procedure starts, the UE transmits the dedicated RACH preambleto the BS. When the UE receives the RACH procedure from the BS, the RACHprocedure is completed.

DL and UL Transmission/Reception Operations

DL Transmission/Reception Operation

DL grants (also called DL assignments) may be classified into (1)dynamic grant and (2) configured grant. A dynamic grant is a datatransmission/reception method based on dynamic scheduling of a BS,aiming to maximize resource utilization.

The BS schedules a DL transmission by DCI. The UE receives the DCI forDL scheduling (i.e., including scheduling information for a PDSCH)(referred to as DL grant DCI) from the BS. The DCI for DL scheduling mayinclude, for example, the following information: a BWP indicator, afrequency-domain resource assignment, a time-domain resource assignment,and a modulation and coding scheme (MCS).

The UE may determine a modulation order, a target code rate, and a TBsize (TBS) for the PDSCH based on an MCS field in the DCI. The UE mayreceive the PDSCH in time-frequency resources according to thefrequency-domain resource assignment and the time-domain resourceassignment.

The DL configured grant is also called semi-persistent scheduling (SPS).The UE may receive an RRC message including a resource configuration forDL data transmission from the BS. In the case of DL SPS, an actual DLconfigured grant is provided by a PDCCH, and the DL SPS is activated ordeactivated by the PDCCH. When DL SPS is configured, the BS provides theUE with at least the following parameters by RRC signaling: a configuredscheduling RNTI (CS-RNTI) for activation, deactivation, andretransmission; and a periodicity. An actual DL grant (e.g., a frequencyresource assignment) for DL SPS is provided to the UE by DCI in a PDCCHaddressed to the CS-RNTI. If a specific field in the DCI of the PDCCHaddressed to the CS-RNTI is set to a specific value for schedulingactivation, SPS associated with the CS-RNTI is activated. The DCI of thePDCCH addressed to the CS-RNTI includes actual frequency resourceallocation information, an MCS index, and so on. The UE may receive DLdata on a PDSCH based on the SPS.

UL Transmission/Reception Operation

UL grants may be classified into (1) dynamic grant that schedules aPUSCH dynamically by UL grant DCI and (2) configured grant thatschedules a PUSCH semi-statically by RRC signaling.

FIG. 5 is a diagram illustrating exemplary UL transmissions according toUL grants. Particularly, FIG. 5(a) illustrates a UL transmissionprocedure based on a dynamic grant, and FIG. 5(b) illustrates a ULtransmission procedure based on a configured grant.

In the case of a UL dynamic grant, the BS transmits DCI including ULscheduling information to the UE. The UE receives DCI for UL scheduling(i.e., including scheduling information for a PUSCH) (referred to as ULgrant DCI) on a PDCCH. The DCI for UL scheduling may include, forexample, the following information: a BWP indicator, a frequency-domainresource assignment, a time-domain resource assignment, and an MCS. Forefficient allocation of UL radio resources by the BS, the UE maytransmit information about UL data to be transmitted to the BS, and theBS may allocate UL resources to the UE based on the information. Theinformation about the UL data to be transmitted is referred to as abuffer status report (BSR), and the BSR is related to the amount of ULdata stored in a buffer of the UE.

Referring to FIG. 5(a), the illustrated UL transmission procedure is fora UE which does not have UL radio resources available for BSRtransmission. In the absence of a UL grant available for UL datatransmission, the UE is not capable of transmitting a BSR on a PUSCH.Therefore, the UE should request resources for UL data, starting withtransmission of an SR on a PUCCH. In this case, a 5-step UL resourceallocation procedure is used.

Referring to FIG. 5(a), in the absence of PUSCH resources for BSRtransmission, the UE first transmits an SR to the BS, for PUSCH resourceallocation. The SR is used for the UE to request PUSCH resources for ULtransmission to the BS, when no PUSCH resources are available to the UEin spite of occurrence of a buffer status reporting event. In thepresence of valid PUCCH resources for the SR, the UE transmits the SR ona PUCCH, whereas in the absence of valid PUCCH resources for the SR, theUE starts the afore-described (contention-based) RACH procedure. Uponreceipt of a UL grant in UL grant DCI from the BS, the UE transmits aBSR to the BS in PUSCH resources allocated by the UL grant. The BSchecks the amount of UL data to be transmitted by the UE based on theBSR and transmits a UL grant in UL grant DCI to the UE. Upon detectionof a PDCCH including the UL grant DCI, the UE transmits actual UL datato the BS on a PUSCH based on the UL grant included in the UL grant DCI.

Referring to FIG. 5(b), in the case of a configured grant, the UEreceives an RRC message including a resource configuration for UL datatransmission from the BS. In the NR system, two types of UL configuredgrants are defined: type 1 and type 2. In the case of UL configuredgrant type 1, an actual UL grant (e.g., time resources and frequencyresources) is provided by RRC signaling, whereas in the case of ULconfigured grant type 2, an actual UL grant is provided by a PDCCH, andactivated or deactivated by the PDCCH. If configured grant type 1 isconfigured, the BS provides the UE with at least the followingparameters by RRC signaling: a CS-RNTI for retransmission; a periodicityof configured grant type 1; information about a starting symbol index Sand the number L of symbols for a PUSCH in a slot; a time-domain offsetrepresenting a resource offset with respect to SFN=0 in the time domain;and an MCS index representing a modulation order, a target code rate,and a TB size. If configured grant type 2 is configured, the BS providesthe UE with at least the following parameters by RRC signaling: aCS-RNTI for activation, deactivation, and retransmission; and aperiodicity of configured grant type 2. An actual UL grant of configuredgrant type 2 is provided to the UE by DCI of a PDCCH addressed to aCS-RNTI. If a specific field in the DCI of the PDCCH addressed to theCS-RNTI is set to a specific value for scheduling activation, configuredgrant type 2 associated with the CS-RNTI is activated. The DCI set to aspecific value for scheduling activation in the PDCCH includes actualfrequency resource allocation information, an MCS index, and so on. TheUE may perform a UL transmission on a PUSCH based on a configured grantof type 1 or type 2.

FIG. 6 is a conceptual diagram illustrating exemplary physical channelprocessing.

Each of the blocks illustrated in FIG. 6 may be performed in acorresponding module of a physical layer block in a transmission device.More specifically, the signal processing depicted in FIG. 6 may beperformed for UL transmission by a processor of a UE described in thepresent disclosure. Signal processing of FIG. 6 except for transformprecoding, with CP-OFDM signal generation instead of SC-FDMA signalgeneration may be performed for DL transmission in a processor of a BSdescribed in the present disclosure. Referring to FIG. 6, UL physicalchannel processing may include scrambling, modulation mapping, layermapping, transform precoding, precoding, RE mapping, and SC-FDMA signalgeneration. The above processes may be performed separately or togetherin the modules of the transmission device. The transform precoding, akind of discrete Fourier transform (DFT), is to spread UL data in aspecial manner that reduces the peak-to-average power ratio (PAPR) of awaveform. OFDM which uses a CP together with transform precoding for DFTspreading is referred to as DFT-s-OFDM, and OFDM using a CP without DFTspreading is referred to as CP-OFDM. An SC-FDMA signal is generated byDFT-s-OFDM. In the NR system, if transform precoding is enabled for UL,transform precoding may be applied optionally. That is, the NR systemsupports two options for a UL waveform: one is CP-OFDM and the other isDFT-s-OFDM. The BS provides RRC parameters to the UE such that the UEdetermines whether to use CP-OFDM or DFT-s-OFDM for a UL transmissionwaveform. FIG. 6 is a conceptual view illustrating UL physical channelprocessing for DFT-s-OFDM. For CP-OFDM, transform precoding is omittedfrom the processes of FIG. 6. For DL transmission, CP-OFDM is used forDL waveform transmission.

Each of the above processes will be described in greater detail. For onecodeword, the transmission device may scramble coded bits of thecodeword by a scrambler and then transmit the scrambled bits on aphysical channel. The codeword is obtained by encoding a TB. Thescrambled bits are modulated to complex-valued modulation symbols by amodulation mapper. The modulation mapper may modulate the scrambled bitsin a predetermined modulation scheme and arrange the modulated bits ascomplex-valued modulation symbols representing positions on a signalconstellation. Pi/2-binay phase shift keying (pi/2-BPSK), m-phase shiftkeying (m-PSK), m-quadrature amplitude modulation (m-QAM), or the likeis available for modulation of the coded data. The complex-valuedmodulation symbols may be mapped to one or more transmission layers by alayer mapper. A complexed-value modulation symbol on each layer may beprecoded by a precoder, for transmission through an antenna port. Iftransform precoding is possible for UL transmission, the precoder mayperform precoding after the complex-valued modulation symbols aresubjected to transform precoding, as illustrated in FIG. 6. The precodermay output antenna-specific symbols by processing the complex-valuedmodulation symbols in a multiple input multiple output (MIMO) schemeaccording to multiple Tx antennas, and distribute the antenna-specificsymbols to corresponding RE mappers. An output z of the precoder may beobtained by multiplying an output y of the layer mapper by an N×Mprecoding matrix, W where N is the number of antenna ports and M is thenumber of layers. The RE mappers map the complex-valued modulationsymbols for the respective antenna ports to appropriate REs in an RBallocated for transmission. The RE mappers may map the complex-valuedmodulation symbols to appropriate subcarriers, and multiplex the mappedsymbols according to users. SC-FDMA signal generators (CP-OFDM signalgenerators, when transform precoding is disabled in DL transmission orUL transmission) may generate complex-valued time domain OFDM symbolsignals by modulating the complex-valued modulation symbols in aspecific modulations scheme, for example, in OFDM. The SC-FDMA signalgenerators may perform inverse fast Fourier transform (IFFT) on theantenna-specific symbols and insert CPs into the time-domainIFFT-processed symbols. The OFDM symbols are subjected todigital-to-analog conversion, frequency upconversion, and so on, andthen transmitted to a reception device through the respective Txantennas, Each of the SC-FDMA signal generators may include an IFFTmodule, a CP inserter, a digital-to-analog converter (DAC), a frequencyupconverter, and so on.

A signal processing procedure of the reception device is performed in areverse order of the signal processing procedure of the transmissiondevice. For details, refer to the above description and FIG. 6.

Now, a description will be given of the PUCCH.

The PUCCH is used for UCI transmission. UCI includes an SR requesting ULtransmission resources, CSI representing a UE-measured DL channel statebased on a DL RS, and/or an HARQ-ACK indicating whether a UE hassuccessfully received DL data.

The PUCCH supports multiple formats, and the PUCCH formats areclassified according to symbol durations, payload sizes, andmultiplexing or non-multiplexing. [Table 1] below lists exemplary PUCCHformats.

TABLE 1 PUCCH length in Number of Format OFDM symbols bits Etc. 0 1-2 ≤2 Sequence selection 1 4-14 ≤2 Sequence modulation 2 1-2  >2 CP-OFDM 34-14 >2 DFT-s-OFDM (no UE multiplexing) 4 4-14 >2 DFT-s-OFDM (Pre DFTorthogonal cover code(OCC))

The BS configures PUCCH resources for the UE by RRC signaling. Forexample, to allocate PUCCH resources, the BS may configure a pluralityof PUCCH resource sets for the UE, and the UE may select a specificPUCCH resource set corresponding to a UCI (payload) size (e.g., thenumber of UCI bits). For example, the UE may select one of the followingPUCCH resource sets according to the number of UCI bits, N_(UCI).

-   -   PUCCH resource set #0, if the number of UCI bits≤2    -   PUCCH resource set #1, if 2<the number of UCI bits≤N₁    -   . . .    -   PUCCH resource set # (K−1), if NK−2<the number of UCI        bits≤N_(K-1)

Herein, K represents the number of PUCCH resource sets (K>1), and Nirepresents the maximum number of UCI bits supported by PUCCH resourceset #i. For example, PUCCH resource set #1 may include resources ofPUCCH format 0 to PUCCH format 1, and the other PUCCH resource sets mayinclude resources of PUCCH format 2 to PUCCH format 4.

Subsequently, the BS may transmit DCI to the UE on a PDCCH, indicating aPUCCH resource to be used for UCI transmission among the PUCCH resourcesof a specific PUCCH resource set by an ACK/NACK resource indicator (ART)in the DCI. The ARI may be used to indicate a PUCCH resource forHARQ-ACK transmission, also called a PUCCH resource indicator (PRI).

Enhanced Mobile Broadband Communication (eMBB)

In the NR system, a massive MIMO environment in which the number ofTx/Rx antennas is significantly increased is under consideration. On theother hand, in an NR system operating at or above 6 GHz, beamforming isconsidered, in which a signal is transmitted with concentrated energy ina specific direction, not omni-directionally, to compensate for rapidpropagation attenuation. Accordingly, there is a need for hybridbeamforming with analog beamforming and digital beamforming incombination according to a position to which a beamforming weightvector/precoding vector is applied, for the purpose of increasedperformance, flexible resource allocation, and easiness offrequency-wise beam control.

Hybrid Beamforming

FIG. 7 is a block diagram illustrating an exemplary transmitter andreceiver for hybrid beamforming.

In hybrid beamforming, a BS or a UE may form a narrow beam bytransmitting the same signal through multiple antennas, using anappropriate phase difference and thus increasing energy only in aspecific direction.

Beam Management (BM)

BM is a series of processes for acquiring and maintaining a set of BS(or transmission and reception point (TRP)) beams and/or UE beamsavailable for DL and UL transmissions/receptions. BM may include thefollowing processes and terminology.

-   -   Beam measurement: the BS or the UE measures the characteristics        of a received beamformed signal.    -   Beam determination: the BS or the UE selects its Tx beam/Rx        beam.    -   Beam sweeping: a spatial domain is covered by using a Tx beam        and/or an Rx beam in a predetermined method for a predetermined        time interval.    -   Beam report: the UE reports information about a signal        beamformed based on a beam measurement.

The BM procedure may be divided into (1) a DL BM procedure using an SSBor CSI-RS and (2) a UL BM procedure using an SRS. Further, each BMprocedure may include Tx beam sweeping for determining a Tx beam and Rxbeam sweeping for determining an Rx beam. The following description willfocus on the DL BM procedure using an SSB.

The DL BM procedure using an SSB may include (1) transmission of abeamformed SSB from the BS and (2) beam reporting of the UE. An SSB maybe used for both of Tx beam sweeping and Rx beam sweeping. SSB-based Rxbeam sweeping may be performed by attempting SSB reception whilechanging Rx beams at the UE.

SSB-based beam reporting may be configured, when CST/beam is configuredin the RRC_CONNECTED state.

-   -   The UE receives information about an SSB resource set used for        BM from the BS. The SSB resource set may be configured with one        or more SSBIs. For each SSB resource set, SSBI 0 to SSBI 63 may        be defined.    -   The UE receives signals in SSB resources from the BS based on        the information about the SSB resource set.    -   When the BS configures the UE with an SSBRI and RSRP reporting,        the UE reports a (best) SSBRI and an RSRP corresponding to the        SSBRI to the BS.

The BS may determine a BS Tx beam for use in DL transmission to the UEbased on a beam report received from the UE.

Beam Failure Recovery (BFR) Procedure

In a beamforming system, radio link failure (RLF) may often occur due torotation or movement of a UE or beamforming blockage. Therefore, BFR issupported to prevent frequent occurrence of RLF in NR.

For beam failure detection, the BS configures beam failure detection RSsfor the UE. If the number of beam failure indications from the physicallayer of the UE reaches a threshold configured by RRC signaling within aperiod configured by RRC signaling of the BS, the UE declares beamfailure.

After the beam failure is detected, the UE triggers BFR by initiating aRACH procedure on a Pcell, and performs BFR by selecting a suitable beam(if the BS provides dedicated RACH resources for certain beams, the UEperforms the RACH procedure for BFR by using the dedicated RACHresources first of all). Upon completion of the RACH procedure, the UEconsiders that the BFR has been completed.

Ultra-Reliable and Low Latency Communication (URLLC)

A URLLC transmission defined in NR may mean a transmission with (1) arelatively small traffic size, (2) a relatively low arrival rate, (3) anextremely low latency requirement (e.g., 0.5 ms or 1 ms), (4) arelatively short transmission duration (e.g., 2 OFDM symbols), and (5)an emergency service/message.

Pre-Emption Indication

Although eMBB and URLLC services may be scheduled in non-overlappedtime/frequency resources, a URLLC transmission may take place inresources scheduled for on-going eMBB traffic. To enable a UE receivinga PDSCH to determine that the PDSCH has been partially punctured due toURLLC transmission of another UE, a preemption indication may be used.The preemption indication may also be referred to as an interruptedtransmission indication.

In relation to a preemption indication, the UE receives DL preemptionRRC information (e.g., a DownlinkPreemption TE) from the BS by RRCsignaling.

The UE receives DCI format 2_1 based on the DL preemption RRCinformation from the BS. For example, the UE attempts to detect a PDCCHconveying preemption indication-related DCI, DCI format 2_1 by using anint-RNTI configured by the DL preemption RRC information.

Upon detection of DCI format 2_1 for serving cell(s) configured by theDL preemption RRC information, the UE may assume that there is notransmission directed to the UE in RBs and symbols indicated by DCIformat 2_1 in a set of RBs and a set of symbols during a monitoringinterval shortly previous to a monitoring interval to which DCI format2_1 belongs. For example, the UE decodes data based on signals receivedin the remaining resource areas, considering that a signal in atime-frequency resource indicated by a preemption indication is not a DLtransmission scheduled for the UE.

Massive MTC (mMTC)

mMTC is one of 5G scenarios for supporting a hyper-connectivity servicein which communication is conducted with multiple UEs at the same time.In this environment, a UE intermittently communicates at a very lowtransmission rate with low mobility. Accordingly, mMTC mainly seeks longoperation of a UE with low cost. In this regard, MTC and narrowband-Internet of things (NB-IoT) handled in the 3GPP will be describedbelow.

The following description is given with the appreciation that atransmission time interval (TTI) of a physical channel is a subframe.For example, a minimum time interval between the start of transmissionof a physical channel and the start of transmission of the next physicalchannel is one subframe. However, a subframe may be replaced with aslot, a mini-slot, or multiple slots in the following description.

Machine Type Communication (MTC)

MTC is an application that does not require high throughput, applicableto machine-to-machine (M2M) or IoT. MTC is a communication technologywhich the 3GPP has adopted to satisfy the requirements of the IoTservice.

While the following description is given mainly of features related toenhanced MTC (eMTC), the same thing is applicable to MTC, eMTC, and MTCto be applied to 5G (or NR), unless otherwise mentioned. The term MTC asused herein may be interchangeable with eMTC, LTE-M1/M2, bandwidthreduced low complexity (BL)/coverage enhanced (CE), non-BL UE (inenhanced coverage), NR MTC, enhanced BL/CE, and so on.

MTC General

(1) MTC Operates Only in a Specific System BW (or Channel BW).

MTC may use a predetermined number of RBs among the RBs of a system bandin the legacy LTE system or the NR system. The operating frequency BW ofMTC may be defined in consideration of a frequency range and asubcarrier spacing in NR. A specific system or frequency BW in which MTCoperates is referred to as an MTC narrowband (NB) or MTC subband. In NR,MTC may operate in at least one BWP or a specific band of a BWP.

While MTC is supported by a cell having a much larger BW (e.g., 10 MHz)than 1.08 MHz, a physical channel and signal transmitted/received in MTCis always limited to 1.08 MHz or 6 (LTE) RBs. For example, a narrowbandis defined as 6 non-overlapped consecutive physical resource blocks(PRBs) in the frequency domain in the LTE system.

In MTC, some DL and UL channels are allocated restrictively within anarrowband, and one channel does not occupy a plurality of narrowbandsin one time unit. FIG. 8(a) is a diagram illustrating an exemplarynarrowband operation, and FIG. 8(b) is a diagram illustrating exemplaryMTC channel repetition with RF retuning.

An MTC narrowband may be configured for a UE by system information orDCI transmitted by a BS.

(2) MTC does not use a channel (defined in legacy LTE or NR) which is tobe distributed across the total system BW of the legacy LTE or NW Forexample, because a legacy LTE PDCCH is distributed across the totalsystem BW, the legacy PDCCH is not used in MTC. Instead, a new controlchannel, MTC PDCCH (MPDCCH) is used in MTC. The MPDCCH istransmitted/received in up to 6 RBs in the frequency domain. In the timedomain, the MPDCCH may be transmitted in one or more OFDM symbolsstarting with an OFDM symbol of a starting OFDM symbol index indicatedby an RRC parameter from the BS among the OFDM symbols of a subframe.

(3) In MTC, PBCH, PRACH, MPDCCH, PDSCH, PUCCH, and PUSCH may betransmitted repeatedly. The MTC repeated transmissions may make thesechannels decodable even when signal quality or power is very poor as ina harsh condition like basement, thereby leading to the effect of anincreased cell radius and signal penetration.

MTC Operation Modes and Levels

For CE, two operation modes, CE Mode A and CE Mode B and four differentCE levels are used in MTC, as listed in [Table 2] below.

TABLE 2 Mode Level Description Mode A Level 1 No repetition for PRACHLevel 2 Small Number of Repetition for PRACH Mode B Level 3 MediumNumber of Repetition for PRACH Level 4 Large Number of Repetition forPRACH

An MTC operation mode is determined by a BS and a CE level is determinedby an MTC UE.

MTC Guard Period

The position of a narrowband used for MTC may change in each specifictime unit (e.g., subframe or slot). An MTC UE may tune to differentfrequencies in different time units. A certain time may be required forfrequency retuning and thus used as a guard period for MTC. Notransmission and reception take place during the guard period.

MTC Signal Transmission/Reception Method

Apart from features inherent to MTC, an MTC signaltransmission/reception procedure is similar to the procedure illustratedin FIG. 2. The operation of S201 in FIG. 2 may also be performed forMTC. A PSS/SSS used in an initial cell search operation in MTC may bethe legacy LTE PSS/SSS.

After acquiring synchronization with a BS by using the PSS/SSS, an MTCUE may acquire broadcast information within a cell by receiving a PBCHsignal from the BS. The broadcast information transmitted on the PBCH isan MIB. In MTC, reserved bits among the bits of the legacy LTE MIB areused to transmit scheduling information for a new system informationblock 1 bandwidth reduced (SIB1-BR). The scheduling information for theSIB1-BR may include information about a repetition number and a TBS fora PDSCH conveying SIB1-BR. A frequency resource assignment for the PDSCHconveying SIB-BR may be a set of 6 consecutive RBs within a narrowband.The SIB-BR is transmitted directly on the PDSCH without a controlchannel (e.g., PDCCH or MPDCCH) associated with SIB-BR.

After completing the initial cell search, the MTC UE may acquire morespecific system information by receiving an MPDCCH and a PDSCH based oninformation of the MPDCCH (S202).

Subsequently, the MTC UE may perform a RACH procedure to completeconnection to the BS (S203 to S206). A basic configuration for the RACHprocedure of the MTC UE may be transmitted in SIB2. Further, SIB2includes paging-related parameters. In the 3GPP system, a pagingoccasion (PO) means a time unit in which a UE may attempt to receivepaging. Paging refers to the network's indication of the presence ofdata to be transmitted to the UE. The MTC UE attempts to receive anMPDCCH based on a P-RNTI in a time unit corresponding to its PO in anarrowband configured for paging, paging narrowband (PNB). When the UEsucceeds in decoding the MPDCCH based on the P-RNTI, the UE may checkits paging message by receiving a PDSCH scheduled by the MPDCCH. In thepresence of its paging message, the UE accesses the network byperforming the RACH procedure.

In MTC, signals and/or messages (Msg1, Msg2, Msg3, and Msg4) may betransmitted repeatedly in the RACH procedure, and a different repetitionpattern may be set according to a CE level.

For random access, PRACH resources for different CE levels are signaledby the BS. Different PRACH resources for up to 4 respective CE levelsmay be signaled to the MTC UE. The MTC UE measures an RSRP using a DL RS(e.g., CRS, CSI-RS, or TRS) and determines one of the CE levels signaledby the BS based on the measurement. The UE selects one of differentPRACH resources (e.g., frequency, time, and preamble resources for aPARCH) for random access based on the determined CE level and transmitsa PRACH. The BS may determine the CE level of the UE based on the PRACHresources that the UE has used for the PRACH transmission. The BS maydetermine a CE mode for the UE based on the CE level that the UEindicates by the PRACH transmission. The BS may transmit DCI to the UEin the CE mode.

Search spaces for an RAR for the PRACH and contention resolutionmessages are signaled in system information by the BS.

After the above procedure, the MTC UE may receive an MPDCCH signaland/or a PDSCH signal (S207) and transmit a PUSCH signal and/or a PUCCHsignal (S208) in a general UL/DL signal transmission procedure. The MTCUE may transmit UCI on a PUCCH or a PUSCH to the BS.

Once an RRC connection for the MTC UE is established, the MTC UEattempts to receive an MDCCH by monitoring an MPDCCH in a configuredsearch space in order to acquire UL and DL data allocations.

In legacy LTE, a PDSCH is scheduled by a PDCCH. Specifically, the PDCCHmay be transmitted in the first N (N=1, 2 or 3) OFDM symbols of asubframe, and the PDSCH scheduled by the PDCCH is transmitted in thesame subframe.

Compared to legacy LTE, an MPDCCH and a PDSCH scheduled by the MPDCCHare transmitted/received in different subframes in MTC. For example, anMPDCCH with a last repetition in subframe #n schedules a PDSCH startingin subframe #n+2. The MPDCCH may be transmitted only once or repeatedly.A maximum repetition number of the MPDCCH is configured for the UE byRRC signaling from the BS. DCI carried on the MPDCCH providesinformation on how many times the MPDCCH is repeated so that the UE maydetermine when the PDSCH transmission starts. For example, if DCI in anMPDCCH starting in subframe #n includes information indicating that theMPDCCH is repeated 10 times, the MPDCCH may end in subframe #n+9 and thePDSCH may start in subframe #n+11. The DCI carried on the MPDCCH mayinclude information about a repetition number for a physical datachannel (e.g., PUSCH or PDSCH) scheduled by the DCI. The UE maytransmit/receive the physical data channel repeatedly in the time domainaccording to the information about the repetition number of the physicaldata channel scheduled by the DCI. The PDSCH may be scheduled in thesame or different narrowband as or from a narrowband in which the MPDCCHscheduling the PDSCH is transmitted. When the MPDCCH and the PDSCH arein different narrowbands, the MTC UE needs to retune to the frequency ofthe narrowband carrying the PDSCH before decoding the PDSCH. For ULscheduling, the same timing as in legacy LTE may be followed. Forexample, an MPDCCH ending in subframe #n may schedule a PUSCHtransmission starting in subframe #n+4. If a physical channel isrepeatedly transmitted, frequency hopping is supported between differentMTC subbands by RF retuning. For example, if a PDSCH is repeatedlytransmitted in 32 subframes, the PDSCH is transmitted in the first 16subframes in a first MTC subband, and in the remaining 16 subframes in asecond MTC subband. MTC may operate in half-duplex mode.

Narrowband-Internet of Things (NB-IoT)

NB-IoT may refer to a system for supporting low complexity, low powerconsumption, and efficient use of frequency resources by a system BWcorresponding to one RB of a wireless communication system (e.g., theLTE system or the NR system). NB-IoT may operate in half-duplex mode.NB-IoT may be used as a communication scheme for implementing IoT bysupporting, for example, an MTC device (or UE) in a cellular system.

In NB-IoT, each UE perceives one RB as one carrier. Therefore, an RB anda carrier as mentioned in relation to NB-IoT may be interpreted as thesame meaning.

While a frame structure, physical channels, multi-carrier operations,and general signal transmission/reception in relation to NB-IoT will bedescribed below in the context of the legacy LTE system, the descriptionis also applicable to the next generation system (e.g., the NR system).Further, the description of NB-IoT may also be applied to MTC servingsimilar technical purposes (e.g., low power, low cost, and coverageenhancement).

NB-IoT Frame Structure and Physical Resources

A different NB-IoT frame structure may be configured according to asubcarrier spacing. For example, for a subcarrier spacing of 15 kHz, theNB-IoT frame structure may be identical to that of a legacy system(e.g., the LTE system). For example, a 10-ms NB-IoT frame may include 101-ms NB-IoT subframes each including two 0.5-ms slots. Each 0.5-msNB-IoT slot may include 7 OFDM symbols. In another example, for a BWP orcell/carrier having a subcarrier spacing of 3.75 kHz, a 10-ms NB-IoTframe may include five 2-ms NB-IoT subframes each including 7 OFDMsymbols and one guard period (GP). Further, a 2-ms NB-IoT subframe maybe represented in NB-IoT slots or NB-IoT resource units (RUs). TheNB-IoT frame structures are not limited to the subcarrier spacings of 15kHz and 3.75 kHz, and NB-IoT for other subcarrier spacings (e.g., 30kHz) may also be considered by changing time/frequency units.

NB-IoT DL physical resources may be configured based on physicalresources of other wireless communication systems (e.g., the LTE systemor the NR system) except that a system BW is limited to a predeterminednumber of RBs (e.g., one RB, that is, 180 kHz). For example, if theNB-IoT DL supports only the 15-kHz subcarrier spacing as describedbefore, the NB-IoT DL physical resources may be configured as a resourcearea in which the resource grid illustrated in FIG. 1 is limited to oneRB in the frequency domain.

Like the NB-IoT DL physical resources, NB-IoT UL resources may also beconfigured by limiting a system BW to one RB. In NB-IoT, the number ofUL subcarriers N^(UL) _(sc) and a slot duration T_(slot) may be given asillustrated in [Table 3] below. In NB-IoT of the LTE system, theduration of one slot, T_(slot) is defined by 7 SC-FDMA symbols in thetime domain.

TABLE 3 Subcarrier spacing N^(UL) _(sc) T_(slot) Δf = 3.75 kHz 48  6144· T_(s) Δf = 15 kHz 12 15360 · T_(s)

In NB-IoT, RUs are used for mapping to REs of a PUSCH for NB-IoT(referred to as an NPUSCH). An RU may be defined by N^(UL)_(symb)*N^(UL) _(slot) SC-FDMA symbols in the time domain by N^(RU)_(sc) consecutive subcarriers in the frequency domain. For example,N^(RU) _(sc) and N^(UL) _(symb) are listed in [Table 4] for acell/carrier having an FDD frame structure and in [Table 5] for acell/carrier having a TDD frame structure.

TABLE 4 NPUSCH format Δf N^(RU) _(sc) N^(UL) _(slots) N^(UL) _(symb) 13.75 kHz 1 16 7 15 kHz 1 16 3 8 6 4 12 2 2 3.75 kHz 1 4 15 kHz 1 4

TABLE 5 Supported NPUSCH uplink-downlink format Δf configuration N^(RU)_(sc) N^(UL) _(slots) N^(UL) _(symb) 1 3.75 kHz 1, 4 1 16 7 15 kHz 1, 2,3, 4, 5 1 16 3 8 6 4 12 2 2 3.75 kHz 1, 4 1 4 15 kHz 1, 2, 3, 4, 5 1 4

NB-IoT Physical Channels

OFDMA may be adopted for NB-IoT DL based on the 15-kHz subcarrierspacing. Because OFDMA provides orthogonality between subcarriers,co-existence with other systems (e.g., the LTE system or the NR system)may be supported efficiently. The names of DL physical channels/signalsof the NB-IoT system may be prefixed with “N (narrowband)” to bedistinguished from their counterparts in the legacy system. For example,DL physical channels may be named NPBCH, NPDCCH, NPDSCH, and so on, andDL physical signals may be named NPSS, NSSS, narrowband reference signal(NRS), narrowband positioning reference signal (NPRS), narrowband wakeup signal (NWUS), and so on. The DL channels, NPBCH, NPDCCH, NPDSCH, andso on may be repeatedly transmitted to enhance coverage in the NB-IOTsystem. Further, new defined DCI formats may be used in NB-IoT, such asDCI format N0, DCI format N1, and DCI format N2.

SC-FDMA may be applied with the 15-kHz or 3.75-kHz subcarrier spacing toNB-IoT UL. As described in relation to DL, the names of physicalchannels of the NB-IoT system may be prefixed with “N (narrowband)” tobe distinguished from their counterparts in the legacy system. Forexample, UL channels may be named NPRACH, NPUSCH, and so on, and ULphysical signals may be named NDMRS and so on. NPUSCHs may be classifiedinto NPUSCH format 1 and NPUSCH format 2. For example, NPUSCH format 1may be used to transmit (or deliver) an uplink shared channel (UL-SCH),and NPUSCH format 2 may be used for UCI transmission such as HARQ ACKsignaling. A UL channel, NPRACH in the NB-IoT system may be repeatedlytransmitted to enhance coverage. In this case, the repeatedtransmissions may be subjected to frequency hopping.

Multi-Carrier Operation in NB-IoT

NB-IoT may be implemented in multi-carrier mode. A multi-carrieroperation may refer to using multiple carriers configured for differentusages (i.e., multiple carriers of different types) intransmitting/receiving channels and/or signals between a BS and a UE.

In the multi-carrier mode in NB-IoT, carriers may be divided into anchortype carrier (i.e., anchor carrier or anchor PRB) and non-anchor typecarrier (i.e., non-anchor carrier or non-anchor PRB).

The anchor carrier may refer to a carrier carrying an NPSS, an NSSS, andan NPBCH for initial access, and an NPDSCH for a system informationblock, N-SIB from the perspective of a BS. That is, a carrier forinitial access is referred to as an anchor carrier, and the othercarrier(s) is referred to as a non-anchor carrier in NB-IoT.

NB-IoT Signal Transmission/Reception Process

In NB-IoT, a signal is transmitted/received in a similar manner to theprocedure illustrated in FIG. 2, except for features inherent to NB-IoT.Referring to FIG. 2, when an NB-IoT UE is powered on or enters a newcell, the NB-IoT UE may perform an initial cell search (S201). For theinitial cell search, the NB-IoT UE may acquire synchronization with a BSand obtain information such as a cell ID by receiving an NPSS and anNSSS from the BS. Further, the NB-IoT UE may acquire broadcastinformation within a cell by receiving an NPBCH from the BS.

Upon completion of the initial cell search, the NB-IoT UE may acquiremore specific system information by receiving an NPDCCH and receiving anNPDSCH corresponding to the NPDCCH (S202). In other words, the BS maytransmit more specific system information to the NB-IoT UE which hascompleted the initial call search by transmitting an NPDCCH and anNPDSCH corresponding to the NPDCCH.

The NB-IoT UE may then perform a RACH procedure to complete a connectionsetup with the BS (S203 to S206). For this purpose, the NB-IoT UE maytransmit a preamble on an NPRACH to the BS (S203). As described before,it may be configured that the NPRACH is repeatedly transmitted based onfrequency hopping, for coverage enhancement. In other words, the BS may(repeatedly) receive the preamble on the NPRACH from the NB-IoT UE. TheNB-IoT UE may then receive an NPDCCH, and a RAR in response to thepreamble on an NPDSCH corresponding to the NPDCCH from the BS (S204). Inother words, the BS may transmit the NPDCCH, and the RAR in response tothe preamble on the NPDSCH corresponding to the NPDCCH to the NB-IoT UE.Subsequently, the NB-IoT UE may transmit an NPUSCH to the BS, usingscheduling information in the RAR (S205) and perform a contentionresolution procedure by receiving an NPDCCH and an NPDSCH correspondingto the NPDCCH (S206).

After the above process, the NB-IoT UE may perform an NPDCCH/NPDSCHreception (S207) and an NPUSCH transmission (S208) in a general UL/DLsignal transmission procedure. In other words, after the above process,the BS may perform an NPDCCH/NPDSCH transmission and an NPUSCH receptionwith the NB-IoT UE in the general UL/DL signal transmission procedure.

In NB-IoT, the NPBCH, the NPDCCH, and the NPDSCH may be transmittedrepeatedly, for coverage enhancement. A UL-SCH (i.e., general UL data)and UCI may be delivered on the PUSCH in NB-IoT. It may be configuredthat the UL-SCH and the UCI are transmitted in different NPUSCH formats(e.g., NPUSCH format 1 and NPUSCH format 2).

In NB-IoT, UCI may generally be transmitted on an NPUSCH. Further, theUE may transmit the NPUSCH periodically, aperiodically, orsemi-persistently according to request/indication of the network (e.g.,BS).

Wireless Communication Apparatus

FIG. 9 is a block diagram of an exemplary wireless communication systemto which proposed methods of the present disclosure are applicable.

Referring to FIG. 9, the wireless communication system includes a firstcommunication device 910 and/or a second communication device 920. Thephrases “A and/or B” and “at least one of A or B” are may be interpretedas the same meaning. The first communication device 910 may be a BS, andthe second communication device 920 may be a UE (or the firstcommunication device 910 may be a UE, and the second communicationdevice 920 may be a BS).

Each of the first communication device 910 and the second communicationdevice 920 includes a processor 911 or 921, a memory 914 or 924, one ormore Tx/Rx RF modules 915 or 925, a Tx processor 912 or 922, an Rxprocessor 913 or 923, and antennas 916 or 926. A Tx/Rx module may alsobe called a transceiver. The processor performs the afore-describedfunctions, processes, and/or methods. More specifically, on DL(communication from the first communication device 910 to the secondcommunication device 920), a higher-layer packet from a core network isprovided to the processor 911. The processor 911 implements Layer 2(i.e., L2) functionalities. On DL, the processor 911 is responsible formultiplexing between a logical channel and a transport channel,provisioning of a radio resource assignment to the second communicationdevice 920, and signaling to the second communication device 920. The Txprocessor 912 executes various signal processing functions of L1 (i.e.,the physical layer). The signal processing functions facilitate forwarderror correction (FEC) of the second communication device 920, includingcoding and interleaving. An encoded and interleaved signal is modulatedto complex-valued modulation symbols after scrambling and modulation.For the modulation, BPSK, QPSK, 16QAM, 64QAM, 246QAM, and so on areavailable according to channels. The complex-valued modulation symbols(hereinafter, referred to as modulation symbols) are divided intoparallel streams. Each stream is mapped to OFDM subcarriers andmultiplexed with an RS in the time and/or frequency domain. A physicalchannel is generated to carry a time-domain OFDM symbol stream bysubjecting the mapped signals to IFFT. The OFDM symbol stream isspatially precoded to multiple spatial streams. Each spatial stream maybe provided to a different antenna 916 through an individual Tx/Rxmodule (or transceiver) 915. Each Tx/Rx module 915 may upconvert thefrequency of each spatial stream to an RF carrier, for transmission. Inthe second communication device 920, each Tx/Rx module (or transceiver)925 receives a signal of the RF carrier through each antenna 926. EachTx/Rx module 925 recovers the signal of the RF carrier to a basebandsignal and provides the baseband signal to the Rx processor 923. The Rxprocessor 923 executes various signal processing functions of L1 (i.e.,the physical layer). The Rx processor 923 may perform spatial processingon information to recover any spatial stream directed to the secondcommunication device 920. If multiple spatial streams are directed tothe second communication device 920, multiple Rx processors may combinethe multiple spatial streams into a single OFDMA symbol stream. The Rxprocessor 923 converts an OFDM symbol stream being a time-domain signalto a frequency-domain signal by FFT. The frequency-domain signalincludes an individual OFDM symbol stream on each subcarrier of an OFDMsignal. Modulation symbols and an RS on each subcarrier are recoveredand demodulated by determining most likely signal constellation pointstransmitted by the first communication device 910. These soft decisionsmay be based on channel estimates. The soft decisions are decoded anddeinterleaved to recover the original data and control signaltransmitted on physical channels by the first communication device 910.The data and control signal are provided to the processor 921.

On UL (communication from the second communication device 920 to thefirst communication device 910), the first communication device 910operates in a similar manner as described in relation to the receiverfunction of the second communication device 920. Each Tx/Rx module 925receives a signal through an antenna 926. Each Tx/Rx module 925 providesan RF carrier and information to the Rx processor 923. The processor 921may be related to the memory 924 storing a program code and data. Thememory 924 may be referred to as a computer-readable medium.

Artificial Intelligence (AI)

Artificial intelligence is a field of studying AI or methodologies forcreating AI, and machine learning is a field of defining various issuesdealt with in the AI field and studying methodologies for addressing thevarious issues. Machine learning is defined as an algorithm thatincreases the performance of a certain operation through steadyexperiences for the operation.

An artificial neural network (ANN) is a model used in machine learningand may generically refer to a model having a problem-solving ability,which is composed of artificial neurons (nodes) forming a network viasynaptic connections. The ANN may be defined by a connection patternbetween neurons in different layers, a learning process for updatingmodel parameters, and an activation function for generating an outputvalue.

The ANN may include an input layer, an output layer, and optionally, oneor more hidden layers. Each layer includes one or more neurons, and theANN may include a synapse that links between neurons. In the ANN, eachneuron may output the function value of the activation function, for theinput of signals, weights, and deflections through the synapse.

Model parameters refer to parameters determined through learning andinclude a weight value of a synaptic connection and deflection ofneurons. A hyperparameter means a parameter to be set in the machinelearning algorithm before learning, and includes a learning rate, arepetition number, a mini batch size, and an initialization function.

The purpose of learning of the ANN may be to determine model parametersthat minimize a loss function. The loss function may be used as an indexto determine optimal model parameters in the learning process of theANN.

Machine learning may be classified into supervised learning,unsupervised learning, and reinforcement learning according to learningmethods.

Supervised learning may be a method of training an ANN in a state inwhich a label for training data is given, and the label may mean acorrect answer (or result value) that the ANN should infer with respectto the input of training data to the ANN. Unsupervised learning may be amethod of training an ANN in a state in which a label for training datais not given. Reinforcement learning may be a learning method in whichan agent defined in a certain environment is trained to select abehavior or a behavior sequence that maximizes cumulative compensationin each state.

Machine learning, which is implemented by a deep neural network (DNN)including a plurality of hidden layers among ANNs, is also referred toas deep learning, and deep learning is part of machine learning. Thefollowing description is given with the appreciation that machinelearning includes deep learning.

<Robot>

A robot may refer to a machine that automatically processes or executesa given task by its own capabilities. Particularly, a robot equippedwith a function of recognizing an environment and performing anoperation based on its decision may be referred to as an intelligentrobot.

Robots may be classified into industrial robots, medical robots,consumer robots, military robots, and so on according to their usages orapplication fields.

A robot may be provided with a driving unit including an actuator or amotor, and thus perform various physical operations such as moving robotjoints. Further, a movable robot may include a wheel, a brake, apropeller, and the like in a driving unit, and thus travel on the groundor fly in the air through the driving unit.

<Self-Driving>

Self-driving refers to autonomous driving, and a self-driving vehiclerefers to a vehicle that travels with no user manipulation or minimumuser manipulation.

For example, self-driving may include a technology of maintaining a lanewhile driving, a technology of automatically adjusting a speed, such asadaptive cruise control, a technology of automatically traveling along apredetermined route, and a technology of automatically setting a routeand traveling along the route when a destination is set.

Vehicles may include a vehicle having only an internal combustionengine, a hybrid vehicle having both an internal combustion engine andan electric motor, and an electric vehicle having only an electricmotor, and may include not only an automobile but also a train, amotorcycle, and the like.

Herein, a self-driving vehicle may be regarded as a robot having aself-driving function.

<eXtended Reality (XR)>

Extended reality is a generical term covering virtual reality (VR),augmented reality (AR), and mixed reality (MR). VR provides a real-worldobject and background only as a computer graphic (CG) image, AR providesa virtual CG image on a real object image, and MR is a computer graphictechnology that mixes and combines virtual objects into the real world.

MR is similar to AR in that the real object and the virtual object areshown together. However, in AR, the virtual object is used as acomplement to the real object, whereas in MR, the virtual object and thereal object are handled equally.

XR may be applied to a head-mounted display (HMD), a head-up display(HUD), a portable phone, a tablet PC, a laptop computer, a desktopcomputer, a TV, a digital signage, and so on. A device to which XR isapplied may be referred to as an XR device.

FIG. 10 illustrates an AI device 1000 according to an embodiment of thepresent disclosure.

The AI device 1000 illustrated in FIG. 10 may be configured as astationary device or a mobile device, such as a TV, a projector, aportable phone, a smartphone, a desktop computer, a laptop computer, adigital broadcasting terminal, a personal digital assistant (PDA), aportable multimedia player (PMP), a navigation device, a tablet PC, awearable device, a set-top box (STB), a digital multimedia broadcasting(DMB) receiver, a radio, a washing machine, a refrigerator, a digitalsignage, a robot, or a vehicle.

Referring to FIG. 10, the AI device 1000 may include a communicationunit 1010, an input unit 1020, a learning processor 1030, a sensing unit1040, an output unit 1050, a memory 1070, and a processor 1080.

The communication unit 1010 may transmit and receive data to and from anexternal device such as another AI device or an AI server by wired orwireless communication. For example, the communication unit 1010 maytransmit and receive sensor information, a user input, a learning model,and a control signal to and from the external device.

Communication schemes used by the communication unit 1010 include globalsystem for mobile communication (GSM), CDMA, LTE, 5G, wireless localarea network (WLAN), wireless fidelity (Wi-Fi), Bluetooth™, radiofrequency identification (RFID), infrared data association (IrDA),ZigBee, near field communication (NFC), and so on. Particularly, the 5Gtechnology described before with reference to FIGS. 1 to 9 may also beapplied.

The input unit 1020 may acquire various types of data. The input unit1020 may include a camera for inputting a video signal, a microphone forreceiving an audio signal, and a user input unit for receivinginformation from a user. The camera or the microphone may be treated asa sensor, and thus a signal acquired from the camera or the microphonemay be referred to as sensing data or sensor information.

The input unit 1020 may acquire training data for model training andinput data to be used to acquire an output by using a learning model.The input unit 1020 may acquire raw input data. In this case, theprocessor 1080 or the learning processor 1030 may extract an inputfeature by preprocessing the input data.

The learning processor 1030 may train a model composed of an ANN byusing training data. The trained ANN may be referred to as a learningmodel. The learning model may be used to infer a result value for newinput data, not training data, and the inferred value may be used as abasis for determination to perform a certain operation.

The learning processor 1030 may perform AI processing together with alearning processor of an AI server.

The learning processor 1030 may include a memory integrated orimplemented in the AI device 1000. Alternatively, the learning processor1030 may be implemented by using the memory 1070, an external memorydirectly connected to the AI device 1000, or a memory maintained in anexternal device.

The sensing unit 1040 may acquire at least one of internal informationabout the AI device 1000, ambient environment information about the AIdevice 1000, and user information by using various sensors.

The sensors included in the sensing unit 1040 may include a proximitysensor, an illumination sensor, an accelerator sensor, a magneticsensor, a gyro sensor, an inertial sensor, a red, green, blue (RGB)sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonicsensor, an optical sensor, a microphone, a light detection and ranging(LiDAR), and a radar.

The output unit 1050 may generate a visual, auditory, or haptic output.

Accordingly, the output unit 1050 may include a display unit foroutputting visual information, a speaker for outputting auditoryinformation, and a haptic module for outputting haptic information.

The memory 1070 may store data that supports various functions of the AIdevice 1000. For example, the memory 1070 may store input data acquiredby the input unit 1020, training data, a learning model, a learninghistory, and so on.

The processor 1080 may determine at least one executable operation ofthe AI device 100 based on information determined or generated by a dataanalysis algorithm or a machine learning algorithm. The processor 1080may control the components of the AI device 1000 to execute thedetermined operation.

To this end, the processor 1080 may request, search, receive, or utilizedata of the learning processor 1030 or the memory 1070. The processor1080 may control the components of the AI device 1000 to execute apredicted operation or an operation determined to be desirable among theat least one executable operation.

When the determined operation needs to be performed in conjunction withan external device, the processor 1080 may generate a control signal forcontrolling the external device and transmit the generated controlsignal to the external device.

The processor 1080 may acquire intention information with respect to auser input and determine the user's requirements based on the acquiredintention information.

The processor 1080 may acquire the intention information correspondingto the user input by using at least one of a speech to text (STT) enginefor converting a speech input into a text string or a natural languageprocessing (NLP) engine for acquiring intention information of a naturallanguage.

At least one of the STT engine or the NLP engine may be configured as anANN, at least part of which is trained according to the machine learningalgorithm. At least one of the STT engine or the NLP engine may betrained by the learning processor, a learning processor of the AIserver, or distributed processing of the learning processors. Forreference, specific components of the AI server are illustrated in FIG.11.

The processor 1080 may collect history information including theoperation contents of the AI device 1000 or the user's feedback on theoperation and may store the collected history information in the memory1070 or the learning processor 1030 or transmit the collected historyinformation to the external device such as the AI server. The collectedhistory information may be used to update the learning model.

The processor 1080 may control at least a part of the components of AIdevice 1000 so as to drive an application program stored in the memory1070. Furthermore, the processor 1080 may operate two or more of thecomponents included in the AI device 1000 in combination so as to drivethe application program.

FIG. 11 illustrates an AI server 1120 according to an embodiment of thepresent disclosure.

Referring to FIG. 11, the AI server 1120 may refer to a device thattrains an ANN by a machine learning algorithm or uses a trained ANN. TheAI server 1120 may include a plurality of servers to perform distributedprocessing, or may be defined as a 5G network. The AI server 1120 may beincluded as part of the AI device 1100, and perform at least part of theAI processing.

The AI server 1120 may include a communication unit 1121, a memory 1123,a learning processor 1122, a processor 1126, and so on.

The communication unit 1121 may transmit and receive data to and from anexternal device such as the AI device 1100.

The memory 1123 may include a model storage 1124. The model storage 1124may store a model (or an ANN 1125) which has been trained or is beingtrained through the learning processor 1122.

The learning processor 1122 may train the ANN 1125 by training data. Thelearning model may be used, while being loaded on the AI server 1120 ofthe ANN, or on an external device such as the AI device 1110.

The learning model may be implemented in hardware, software, or acombination of hardware and software. If all or part of the learningmodel is implemented in software, one or more instructions of thelearning model may be stored in the memory 1123.

The processor 1126 may infer a result value for new input data by usingthe learning model and may generate a response or a control commandbased on the inferred result value.

FIG. 12 illustrates an AI system according to an embodiment of thepresent disclosure.

Referring to FIG. 12, in the AI system, at least one of an AI server1260, a robot 1210, a self-driving vehicle 1220, an XR device 1230, asmartphone 1240, or a home appliance 1250 is connected to a cloudnetwork 1200. The robot 1210, the self-driving vehicle 1220, the XRdevice 1230, the smartphone 1240, or the home appliance 1250, to whichAI is applied, may be referred to as an AI device.

The cloud network 1200 may refer to a network that forms part of cloudcomputing infrastructure or exists in the cloud computinginfrastructure. The cloud network 1200 may be configured by using a 3Gnetwork, a 4G or LTE network, or a 5G network.

That is, the devices 1210 to 1260 included in the AI system may beinterconnected via the cloud network 1200. In particular, each of thedevices 1210 to 1260 may communicate with each other directly or througha BS.

The AI server 1260 may include a server that performs AI processing anda server that performs computation on big data.

The AI server 1260 may be connected to at least one of the AI devicesincluded in the AI system, that is, at least one of the robot 1210, theself-driving vehicle 1220, the XR device 1230, the smartphone 1240, orthe home appliance 1250 via the cloud network 1200, and may assist atleast part of AI processing of the connected AI devices 1210 to 1250.

The AI server 1260 may train the ANN according to the machine learningalgorithm on behalf of the AI devices 1210 to 1250, and may directlystore the learning model or transmit the learning model to the AIdevices 1210 to 1250.

The AI server 1260 may receive input data from the AI devices 1210 to1250, infer a result value for received input data by using the learningmodel, generate a response or a control command based on the inferredresult value, and transmit the response or the control command to the AIdevices 1210 to 1250.

Alternatively, the AI devices 1210 to 1250 may infer the result valuefor the input data by directly using the learning model, and generatethe response or the control command based on the inference result.

Hereinafter, various embodiments of the AI devices 1210 to 1250 to whichthe above-described technology is applied will be described. The AIdevices 1210 to 1250 illustrated in FIG. 12 may be regarded as aspecific embodiment of the AI device 1000 illustrated in FIG. 10.

<AI+XR>

The XR device 1230, to which AI is applied, may be configured as a HMD,a HUD provided in a vehicle, a TV, a portable phone, a smartphone, acomputer, a wearable device, a home appliance, a digital signage, avehicle, a fixed robot, a mobile robot, or the like.

The XR device 1230 may acquire information about a surrounding space ora real object by analyzing 3D point cloud data or image data acquiredfrom various sensors or an external device and thus generating positiondata and attribute data for the 3D points, and may render an XR objectto be output. For example, the XR device 1230 may output an XR objectincluding additional information about a recognized object incorrespondence with the recognized object.

The XR device 1230 may perform the above-described operations by usingthe learning model composed of at least one ANN. For example, the XRdevice 1230 may recognize a real object from 3D point cloud data orimage data by using the learning model, and may provide informationcorresponding to the recognized real object. The learning model may betrained directly by the XR device 1230 or by the external device such asthe AI server 1260.

While the XR device 1230 may operate by generating a result by directlyusing the learning model, the XR device 1230 may operate by transmittingsensor information to the external device such as the AI server 1260 andreceiving the result.

<AI+Robot+XR>

The robot 1210, to which AI and XR are applied, may be implemented as aguide robot, a delivery robot, a cleaning robot, a wearable robot, anentertainment robot, a pet robot, an unmanned flying robot, a drone, orthe like.

The robot 1210, to which XR is applied, may refer to a robot to becontrolled/interact within an XR image. In this case, the robot 1210 maybe distinguished from the XR device 1230 and interwork with the XRdevice 1230.

When the robot 1210 to be controlled/interact within an XR imageacquires sensor information from sensors each including a camera, therobot 1210 or the XR device 1230 may generate an XR image based on thesensor information, and the XR device 1230 may output the generated XRimage. The robot 1210 may operate based on the control signal receivedthrough the XR device 1230 or based on the user's interaction.

For example, the user may check an XR image corresponding to a view ofthe robot 1210 interworking remotely through an external device such asthe XR device 1210, adjust a self-driving route of the robot 1210through interaction, control the operation or driving of the robot 1210,or check information about an ambient object around the robot 1210.

<AI+Self-Driving+XR>

The self-driving vehicle 1220, to which AT and XR are applied, may beimplemented as a mobile robot, a vehicle, an unmanned flying vehicle, orthe like.

The self-driving driving vehicle 1220, to which XR is applied, may referto a self-driving vehicle provided with a means for providing an XRimage or a self-driving vehicle to be controlled/interact within an XRimage. Particularly, the self-driving vehicle 1220 to becontrolled/interact within an XR image may be distinguished from the XRdevice 1230 and interwork with the XR device 1230.

The self-driving vehicle 1220 provided with the means for providing anXR image may acquire sensor information from the sensors each includinga camera and output the generated XR image based on the acquired sensorinformation. For example, the self-driving vehicle 1220 may include anHUD to output an XR image, thereby providing a passenger with an XRobject corresponding to a real object or an object on the screen.

When the XR object is output to the HUD, at least part of the XR objectmay be output to be overlaid on an actual object to which thepassenger's gaze is directed. When the XR object is output to a displayprovided in the self-driving vehicle 1220, at least part of the XRobject may be output to be overlaid on the object within the screen. Forexample, the self-driving vehicle 1220 may output XR objectscorresponding to objects such as a lane, another vehicle, a trafficlight, a traffic sign, a two-wheeled vehicle, a pedestrian, a building,and so on.

When the self-driving vehicle 1220 to be controlled/interact within anXR image acquires sensor information from the sensors each including acamera, the self-driving vehicle 1220 or the XR device 1230 may generatethe XR image based on the sensor information, and the XR device 1230 mayoutput the generated XR image. The self-driving vehicle 1220 may operatebased on a control signal received through an external device such asthe XR device 1230 or based on the user's interaction.

VR, AR, and MR technologies of the present disclosure are applicable tovarious devices, particularly, for example, a HMD, a HUD attached to avehicle, a portable phone, a tablet PC, a laptop computer, a desktopcomputer, a TV, and a signage. The VR, AR, and MR technologies may alsobe applicable to a device equipped with a flexible or rollable display.

The above-described VR, AR, and MR technologies may be implemented basedon CG and distinguished by the ratios of a CG image in an image viewedby the user.

That is, VR provides a real object or background only in a CG image,whereas AR overlays a virtual CG image on an image of a real object.

MR is similar to AR in that virtual objects are mixed and combined witha real world. However, a real object and a virtual object created as aCG image are distinctive from each other and the virtual object is usedto complement the real object in AR, whereas a virtual object and a realobject are handled equally in MR. More specifically, for example, ahologram service is an MR representation.

These days, VR, AR, and MR are collectively called XR withoutdistinction among them. Therefore, embodiments of the present disclosureare applicable to all of VR, AR, MR, and XR.

For example, wired/wireless communication, input interfacing, outputinterfacing, and computing devices are available as hardware(HW)-related element techniques applied to VR, AR, MR, and XR. Further,tracking and matching, speech recognition, interaction and userinterfacing, location-based service, search, and AI are available assoftware (SW)-related element techniques.

Particularly, the embodiments of the present disclosure are intended toaddress at least one of the issues of communication with another device,efficient memory use, data throughput decrease caused by inconvenientuser experience/user interface (UX/UI), video, sound, motion sickness,or other issues.

FIG. 13 is a block diagram illustrating an XR device according toembodiments of the present disclosure. The XR device 1300 includes acamera 1310, a display 1320, a sensor 1330, a processor 1340, a memory1350, and a communication module 1360. Obviously, one or more of themodules may be deleted or modified, and one or more modules may be addedto the modules, when needed, without departing from the scope and spiritof the present disclosure.

The communication module 1360 may communicate with an external device ora server, wiredly or wirelessly. The communication module 1360 may use,for example, Wi-Fi, Bluetooth, or the like, for short-range wirelesscommunication, and for example, a 3GPP communication standard forlong-range wireless communication. LTE is a technology beyond 3GPP TS36.xxx Release 8. Specifically, LTE beyond 3GPP TS 36.xxx Release 10 isreferred to as LTE-A, and LTE beyond 3GPP TS 36.xxx Release 13 isreferred to as LTE-A pro. 3GPP 5G refers to a technology beyond TS36.xxx Release 15 and a technology beyond TS 38.XXX Release 15.Specifically, the technology beyond TS 38.xxx Release 15 is referred toas 3GPP NR, and the technology beyond TS 36.xxx Release 15 is referredto as enhanced LTE. “xxx” represents the number of a technicalspecification. LTE/NR may be collectively referred to as a 3GPP system.

The camera 1310 may capture an ambient environment of the XR device 1300and convert the captured image to an electric signal. The image, whichhas been captured and converted to an electric signal by the camera1310, may be stored in the memory 1350 and then displayed on the display1320 through the processor 1340. Further, the image may be displayed onthe display 1320 by the processor 1340, without being stored in thememory 1350. Further, the camera 110 may have a field of view (FoV). TheFoV is, for example, an area in which a real object around the camera1310 may be detected. The camera 1310 may detect only a real objectwithin the FoV. When a real object is located within the FoV of thecamera 1310, the XR device 1300 may display an AR object correspondingto the real object. Further, the camera 1310 may detect an angle betweenthe camera 1310 and the real object.

The sensor 1330 may include at least one sensor. For example, the sensor1330 includes a sensing means such as a gravity sensor, a geomagneticsensor, a motion sensor, a gyro sensor, an accelerator sensor, aninclination sensor, a brightness sensor, an altitude sensor, anolfactory sensor, a temperature sensor, a depth sensor, a pressuresensor, a bending sensor, an audio sensor, a video sensor, a globalpositioning system (GPS) sensor, and a touch sensor. Further, althoughthe display 1320 may be of a fixed type, the display 1320 may beconfigured as a liquid crystal display (LCD), an organic light emittingdiode (OLED) display, an electroluminescent display (ELD), or a microLED (M-LED) display, to have flexibility. Herein, the sensor 1330 isdesigned to detect a bending degree of the display 1320 configured asthe afore-described LCD, OLED display, ELD, or M-LED display.

The memory 1350 is equipped with a function of storing all or a part ofresult values obtained by wired/wireless communication with an externaldevice or a service as well as a function of storing an image capturedby the camera 1310. Particularly, considering the trend toward increasedcommunication data traffic (e.g., in a 5G communication environment),efficient memory management is required. In this regard, a descriptionwill be given below with reference to FIG. 14.

FIG. 14 is a detailed block diagram of the memory 1350 illustrated inFIG. 13. With reference to FIG. 14, a swap-out process between a randomaccess memory (RAM) and a flash memory according to an embodiment of thepresent disclosure will be described.

When swapping out AR/VR page data from a RAM 1410 to a flash memory1420, a controller 1430 may swap out only one of two or more AR/VR pagedata of the same contents among AR/VR page data to be swapped out to theflash memory 1420.

That is, the controller 1430 may calculate an identifier (e.g., a hashfunction) that identifies each of the contents of the AR/VR page data tobe swapped out, and determine that two or more AR/VR page data havingthe same identifier among the calculated identifiers contain the samecontents. Accordingly, the problem that the lifetime of an AR/VR deviceincluding the flash memory 1420 as well as the lifetime of the flashmemory 1420 is reduced because unnecessary AR/VR page data is stored inthe flash memory 1420 may be overcome.

The operations of the controller 1430 may be implemented in software orhardware without departing from the scope of the present disclosure.More specifically, the memory illustrated in FIG. 14 is included in aHMD, a vehicle, a portable phone, a tablet PC, a laptop computer, adesktop computer, a TV, a signage, or the like, and executes a swapfunction.

A device according to embodiments of the present disclosure may process3D point cloud data to provide various services such as VR, AR, MR, XR,and self-driving to a user.

A sensor collecting 3D point cloud data may be any of, for example, aLiDAR, a red, green, blue depth (RGB-D), and a 3D laser scanner. Thesensor may be mounted inside or outside of a HMD, a vehicle, a portablephone, a tablet PC, a laptop computer, a desktop computer, a TV, asignage, or the like.

FIG. 15 illustrates a point cloud data processing system.

Referring to FIG. 15, a point cloud processing system 1500 includes atransmission device which acquires, encodes, and transmits point clouddata, and a reception device which acquires point cloud data byreceiving and decoding video data. As illustrated in FIG. 15, pointcloud data according to embodiments of the present disclosure may beacquired by capturing, synthesizing, or generating the point cloud data(S1510). During the acquisition, data (e.g., a polygon file format orstandard triangle format (PLY) file) of 3D positions (x, y,z)/attributes (color, reflectance, transparency, and so on) of pointsmay be generated. For a video of multiple frames, one or more files maybe acquired. Point cloud data-related metadata (e.g., metadata relatedto capturing) may be generated during the capturing. The transmissiondevice or encoder according to embodiments of the present disclosure mayencode the point cloud data by video-based point cloud compression(V-PCC) or geometry-based point cloud compression (G-PCC), and outputone or more video streams (S1520). V-PCC is a scheme of compressingpoint cloud data based on a 2D video codec such as high efficiency videocoding (HEVC) or versatile video coding (VVC), G-PCC is a scheme ofencoding point cloud data separately into two streams: geometry andattribute. The geometry stream may be generated by reconstructing andencoding position information about points, and the attribute stream maybe generated by reconstructing and encoding attribute information (e.g.,color) related to each point. In V-PCC, despite compatibility with a 2Dvideo, much data is required to recover V-PCC-processed data (e.g.,geometry video, attribute video, occupancy map video, and auxiliaryinformation), compared to G-PCC, thereby causing a long latency inproviding a service. One or more output bit streams may be encapsulatedalong with related metadata in the form of a file (e.g., a file formatsuch as ISOBMFF) and transmitted over a network or through a digitalstorage medium (S1530).

The device or processor according to embodiments of the presentdisclosure may acquire one or more bit streams and related metadata bydecapsulating the received video data, and recover 3D point cloud databy decoding the acquired bit streams in V-PCC or G-PCC (S1540). Arenderer may render the decoded point cloud data and provide contentsuitable for VR/AR/MR/service to the user on a display (S1550).

As illustrated in FIG. 15, the device or processor according toembodiments of the present disclosure may perform a feedback process oftransmitting various pieces of feedback information acquired during therendering/display to the transmission device or to the decoding process(S1560). The feedback information according to embodiments of thepresent disclosure may include head orientation information, viewportinformation indicating an area that the user is viewing, and so on.Because the user interacts with a service (or content) provider throughthe feedback process, the device according to embodiments of the presentdisclosure may provide a higher data processing speed by using theafore-described V-PCC or G-PCC scheme or may enable clear videoconstruction as well as provide various services in consideration ofhigh user convenience.

FIG. 16 is a block diagram of an XR device 1600 including a learningprocessor. Compared to FIG. 13, only a learning processor 1670 is added,and thus a redundant description is avoided because FIG. 13 may bereferred to for the other components.

Referring to FIG. 16, the XR device 1600 may be loaded with a learningmodel. The learning model may be implemented in hardware, software, or acombination of hardware and software. If the whole or part of thelearning model is implemented in software, one or more instructions thatform the learning model may be stored in a memory 1650.

According to embodiments of the present disclosure, a learning processor1670 may be coupled communicably to a processor 1640, and repeatedlytrain a model including ANNs by using training data. An ANN is aninformation processing system in which multiple neurons are linked inlayers, modeling an operation principle of biological neurons and linksbetween neurons. An ANN is a statistical learning algorithm inspired bya neural network (particularly the brain in the central nervous systemof an animal) in machine learning and cognitive science. Machinelearning is one field of AI, in which the ability of learning without anexplicit program is granted to a computer. Machine learning is atechnology of studying and constructing a system for learning,predicting, and improving its capability based on empirical data, and analgorithm for the system. Therefore, according to embodiments of thepresent disclosure, the learning processor 1670 may infer a result valuefrom new input data by determining optimized model parameters of an ANN.Therefore, the learning processor 1670 may analyze a device use patternof a user based on device use history information about the user.Further, the learning processor 1670 may be configured to receive,classify, store, and output information to be used for data mining, dataanalysis, intelligent decision, and a machine learning algorithm andtechnique.

According to embodiments of the present disclosure, the processor 1640may determine or predict at least one executable operation of the devicebased on data analyzed or generated by the learning processor 1670.Further, the processor 1640 may request, search, receive, or use data ofthe learning processor 1670, and control the XR device 1600 to perform apredicted operation or an operation determined to be desirable among theat least one executable operation. According to embodiments of thepresent disclosure, the processor 1640 may execute various functions ofrealizing intelligent emulation (i.e., knowledge-based system, reasoningsystem, and knowledge acquisition system). The various functions may beapplied to an adaptation system, a machine learning system, and varioustypes of systems including an ANN (e.g., a fuzzy logic system). That is,the processor 1640 may predict a user's device use pattern based on dataof a use pattern analyzed by the learning processor 1670, and controlthe XR device 1600 to provide a more suitable XR service to the UE.Herein, the XR service includes at least one of the AR service, the VRservice, or the MR service.

FIG. 17 illustrates a process of providing an XR service by the XRservice 1600 of the present disclosure illustrated in FIG. 16.

According to embodiments of the present disclosure, the processor 1670may store device use history information about a user in the memory 1650(S1710). The device use history information may include informationabout the name, category, and contents of content provided to the user,information about a time at which a device has been used, informationabout a place in which the device has been used, time information, andinformation about use of an application installed in the device.

According to embodiments of the present disclosure, the learningprocessor 1670 may acquire device use pattern information about the userby analyzing the device use history information (S1720). For example,when the XR device 1600 provides specific content A to the user, thelearning processor 1670 may learn information about a pattern of thedevice used by the user using the corresponding terminal by combiningspecific information about content A (e.g., information about the agesof users that generally use content A, information about the contents ofcontent A, and content information similar to content A), andinformation about the time points, places, and number of times in whichthe user using the corresponding terminal has consumed content A.

According to embodiments of the present disclosure, the processor 1640may acquire the user device pattern information generated based on theinformation learned by the learning processor 1670, and generate deviceuse pattern prediction information (S1730). Further, when the user isnot using the device 1600, if the processor 1640 determines that theuser is located in a place where the user has frequently used the device1600, or it is almost time for the user to usually use the device 1600,the processor 1640 may indicate the device 1600 to operate. In thiscase, the device according to embodiments of the present disclosure mayprovide AR content based on the user pattern prediction information(S1740).

When the user is using the device 1600, the processor 1640 may checkinformation about content currently provided to the user, and generatedevice use pattern prediction information about the user in relation tothe content (e.g., when the user requests other related content oradditional data related to the current content). Further, the processor1640 may provide AR content based on the device use pattern predictioninformation by indicating the device 1600 to operate (S1740). The ARcontent according to embodiments of the present disclosure may includean advertisement, navigation information, danger information, and so on.

FIG. 18 illustrates the outer appearances of an XR device and a robot.

Component modules of an XR device 1800 according to an embodiment of thepresent disclosure have been described before with reference to theprevious drawings, and thus a redundant description is not providedherein.

The outer appearance of a robot 1810 illustrated in FIG. 18 is merely anexample, and the robot 1810 may be implemented to have various outerappearances according to the present disclosure. For example, the robot1810 illustrated in FIG. 18 may be a drone, a cleaner, a cook root, awearable robot, or the like. Particularly, each component of the robot1810 may be disposed at a different position such as up, down, left,right, back, or forth according to the shape of the robot 1810.

The robot 1810 may be provided, on the exterior thereof, with varioussensors to identify ambient objects. Further, to provide specificinformation to a user, the robot 1810 may be provided with an interfaceunit 1811 on top or the rear surface 1812 thereof.

To sense movement of the robot 1810 and an ambient object, and controlthe robot 1810, a robot control module 1850 is mounted inside the robot1810. The robot control module 1850 may be implemented as a softwaremodule or a hardware chip with the software module implemented therein.The robot control module 1850 may include a deep learner 1851, a sensinginformation processor 1852, a movement path generator 1853, and acommunication module 1854.

The sensing information processor 1852 collects and processesinformation sensed by various types of sensors (e.g., a LiDAR sensor, anIR sensor, an ultrasonic sensor, a depth sensor, an image sensor, and amicrophone) arranged in the robot 1810.

The deep learner 1851 may receive information processed by the sensinginformation processor 1851 or accumulative information stored duringmovement of the robot 1810, and output a result required for the robot1810 to determine an ambient situation, process information, or generatea moving path.

The moving path generator 1852 may calculate a moving path of the robot1810 by using the data calculated by the deep learner 8151 or the dataprocessed by the sensing information processor 1852.

Because each of the XR device 1800 and the robot 1810 is provided with acommunication module, the XR device 1800 and the robot 1810 may transmitand receive data by short-range wireless communication such as Wi-Fi orBluetooth, or 5G long-range wireless communication. A technique ofcontrolling the robot 1810 by using the XR device 1800 will be describedbelow with reference to FIG. 19.

FIG. 19 is a flowchart illustrating a process of controlling a robot byusing an XR device.

The XR device and the robot are connected communicably to a 5G network(S1901). Obviously, the XR device and the robot may transmit and receivedata by any other short-range or long-range communication technologywithout departing from the scope of the present disclosure.

The robot captures an image/video of the surroundings of the robot bymeans of at least one camera installed on the interior or exterior ofthe robot (S1902) and transmits the captured image/video to the XRdevice (S1903). The XR device displays the captured image/video (S1904)and transmits a command for controlling the robot to the robot (S1905).The command may be input manually by a user of the XR device orautomatically generated by AI without departing from the scope of thedisclosure.

The robot executes a function corresponding to the command received instep S1905 (S1906) and transmits a result value to the XR device(S1907). The result value may be a general indicator indicating whetherdata has been successfully processed or not, a current captured image,or specific data in which the XR device is considered. The specific datais designed to change, for example, according to the state of the XRdevice. If a display of the XR device is in an off state, a command forturning on the display of the XR device is included in the result valuein step S1907. Therefore, when an emergency situation occurs around therobot, even though the display of the remote XR device is turned off, anotification message may be transmitted.

AR/VR content is displayed according to the result value received instep S1907 (S1908).

According to another embodiment of the present disclosure, the XR devicemay display position information about the robot by using a GPS moduleattached to the robot.

The XR device 1300 described with reference to FIG. 13 may be connectedto a vehicle that provides a self-driving service in a manner thatallows wired/wireless communication, or may be mounted on the vehiclethat provides the self-driving service. Accordingly, various servicesincluding AR/VR may be provided even in the vehicle that provides theself-driving service.

FIG. 20 illustrates a vehicle that provides a self-driving service.

According to embodiments of the present disclosure, a vehicle 2010 mayinclude a car, a train, and a motor bike as transportation meanstraveling on a road or a railway. According to embodiments of thepresent disclosure, the vehicle 2010 may include all of an internalcombustion engine vehicle provided with an engine as a power source, ahybrid vehicle provided with an engine and an electric motor as a powersource, and an electric vehicle provided with an electric motor as apower source.

According to embodiments of the present disclosure, the vehicle 2010 mayinclude the following components in order to control operations of thevehicle 2010: a user interface device, an object detection device, acommunication device, a driving maneuver device, a main electroniccontrol unit (ECU), a drive control device, a self-driving device, asensing unit, and a position data generation device.

Each of the user interface device, the object detection device, thecommunication device, the driving maneuver device, the main ECU, thedrive control device, the self-driving device, the sensing unit, and theposition data generation device may generate an electric signal, and beimplemented as an electronic device that exchanges electric signals.

The user interface device may receive a user input and provideinformation generated from the vehicle 2010 to a user in the form of aUI or UX. The user interface device may include an input/output (I/O)device and a user monitoring device. The object detection device maydetect the presence or absence of an object outside of the vehicle 2010,and generate information about the object. The object detection devicemay include at least one of, for example, a camera, a LiDAR, an IRsensor, or an ultrasonic sensor. The camera may generate informationabout an object outside of the vehicle 2010. The camera may include oneor more lenses, one or more image sensors, and one or more processorsfor generating object information. The camera may acquire informationabout the position, distance, or relative speed of an object by variousimage processing algorithms. Further, the camera may be mounted at aposition where the camera may secure an FoV in the vehicle 2010, tocapture an image of the surroundings of the vehicle 1020, and may beused to provide an AR/VR-based service. The LiDAR may generateinformation about an object outside of the vehicle 2010. The LiDAR mayinclude a light transmitter, a light receiver, and at least oneprocessor which is electrically coupled to the light transmitter and thelight receiver, processes a received signal, and generates data about anobject based on the processed signal.

The communication device may exchange signals with a device (e.g.,infrastructure such as a server or a broadcasting station), anothervehicle, or a terminal) outside of the vehicle 2010. The drivingmaneuver device is a device that receives a user input for driving. Inmanual mode, the vehicle 2010 may travel based on a signal provided bythe driving maneuver device. The driving maneuver device may include asteering input device (e.g., a steering wheel), an acceleration inputdevice (e.g., an accelerator pedal), and a brake input device (e.g., abrake pedal).

The sensing unit may sense a state of the vehicle 2010 and generatestate information. The position data generation device may generateposition data of the vehicle 2010. The position data generation devicemay include at least one of a GPS or a differential global positioningsystem (DGPS). The position data generation device may generate positiondata of the vehicle 2010 based on a signal generated from at least oneof the GPS or the DGPS. The main ECU may provide overall control to atleast one electronic device provided in the vehicle 2010, and the drivecontrol device may electrically control a vehicle drive device in thevehicle 2010.

The self-driving device may generate a path for the self-driving servicebased on data acquired from the object detection device, the sensingunit, the position data generation device, and so on. The self-drivingdevice may generate a driving plan for driving along the generated path,and generate a signal for controlling movement of the vehicle accordingto the driving plan. The signal generated from the self-driving deviceis transmitted to the drive control device, and thus the drive controldevice may control the vehicle drive device in the vehicle 2010.

As illustrated in FIG. 20, the vehicle 2010 that provides theself-driving service is connected to an XR device 2000 in a manner thatallows wired/wireless communication. The XR device 2000 may include aprocessor 2001 and a memory 2002. While not shown, the XR device 2000 ofFIG. 20 may further include the components of the XR device 1300described before with reference to FIG. 13.

If the XR device 2000 is connected to the vehicle 2010 in a manner thatallows wired/wireless communication. The XR device 2000 mayreceive/process AR/VR service-related content data that may be providedalong with the self-driving service, and transmit the received/processedAR/VR service-related content data to the vehicle 2010. Further, whenthe XR device 2000 is mounted on the vehicle 2010, the XR device 2000may receive/process AR/VR service-related content data according to auser input signal received through the user interface device and providethe received/processed AR/VR service-related content data to the user.In this case, the processor 2001 may receive/process the AR/VRservice-related content data based on data acquired from the objectdetection device, the sensing unit, the position data generation device,the self-driving device, and so on. According to embodiments of thepresent disclosure, the AR/VR service-related content data may includeentertainment content, weather information, and so on which are notrelated to the self-driving service as well as information related tothe self-driving service such as driving information, path informationfor the self-driving service, driving maneuver information, vehiclestate information, and object information.

FIG. 21 illustrates a process of providing an AR/VR service during aself-driving service.

According to embodiments of the present disclosure, a vehicle or a userinterface device may receive a user input signal (S2110). According toembodiments of the present disclosure, the user input signal may includea signal indicating a self-driving service. According to embodiments ofthe present disclosure, the self-driving service may include a fullself-driving service and a general self-driving service. The fullself-driving service refers to perfect self-driving of a vehicle to adestination without a user's manual driving, whereas the generalself-driving service refers to driving a vehicle to a destinationthrough a user's manual driving and self-driving in combination.

It may be determined whether the user input signal according toembodiments of the present disclosure corresponds to the fullself-driving service (S2120). When it is determined that the user inputsignal corresponds to the full self-driving service, the vehicleaccording to embodiments of the present disclosure may provide the fullself-driving service (S2130). Because the full self-driving service doesnot need the user's manipulation, the vehicle according to embodimentsof the present disclosure may provide VR service-related content to theuser through a window of the vehicle, a side mirror of the vehicle, anHMD, or a smartphone (S2130). The VR service-related content accordingto embodiments of the present disclosure may be content related to fullself-driving (e.g., navigation information, driving information, andexternal object information), and may also be content which is notrelated to full self-driving according to user selection (e.g., weatherinformation, a distance image, a nature image, and a voice call image).

If it is determined that the user input signal does not correspond tothe full self-driving service, the vehicle according to embodiments ofthe present disclosure may provide the general self-driving service(S2140). Because the FoV of the user should be secured for the user'smanual driving in the general self-driving service, the vehicleaccording to embodiments of the present disclosure may provide ARservice-related content to the user through a window of the vehicle, aside mirror of the vehicle, an HMD, or a smartphone (S2140).

The AR service-related content according to embodiments of the presentdisclosure may be content related to full self-driving (e.g., navigationinformation, driving information, and external object information), andmay also be content which is not related to self-driving according touser selection (e.g., weather information, a distance image, a natureimage, and a voice call image).

While the present disclosure is applicable to all the fields of 5Gcommunication, robot, self-driving, and AI as described before, thefollowing description will be given mainly of the present disclosureapplicable to an XR device with reference to following figures.

FIG. 22 is a conceptual diagram illustrating an exemplary method forimplementing the XR device using an HMD type according to an embodimentof the present disclosure. The above-mentioned embodiments may also beimplemented in HMD types shown in FIG. 22.

The HMD-type XR device 100 a shown in FIG. 22 may include acommunication unit 110, a control unit 120, a memory unit 130, aninput/output (I/O) unit 140 a, a sensor unit 140 b, a power-supply unit140 c, etc. Specifically, the communication unit 110 embedded in the XRdevice 10 a may communicate with a mobile terminal 100 b by wire orwirelessly.

FIG. 23 is a conceptual diagram illustrating an exemplary method forimplementing an XR device using AR glasses according to an embodiment ofthe present disclosure. The above-mentioned embodiments may also beimplemented in AR glass types shown in FIG. 23.

Referring to FIG. 23, the AR glasses may include a frame, a control unit200, and an optical display unit 300.

Although the frame may be formed in a shape of glasses worn on the faceof the user 10 as shown in FIG. 23, the scope or spirit of the presentdisclosure is not limited thereto, and it should be noted that the framemay also be formed in a shape of goggles worn in close contact with theface of the user 10.

The frame may include a front frame 110 and first and second sideframes.

The front frame 110 may include at least one opening, and may extend ina first horizontal direction (i.e., an X-axis direction). The first andsecond side frames may extend in the second horizontal direction (i.e.,a Y-axis direction) perpendicular to the front frame 110, and may extendin parallel to each other.

The control unit 200 may generate an image to be viewed by the user 10or may generate the resultant image formed by successive images. Thecontrol unit 200 may include an image source configured to create andgenerate images, a plurality of lenses configured to diffuse andconverge light generated from the image source, and the like. The imagesgenerated by the control unit 200 may be transferred to the opticaldisplay unit 300 through a guide lens P200 disposed between the controlunit 200 and the optical display unit 300.

The controller 200 may be fixed to any one of the first and second sideframes. For example, the control unit 200 may be fixed to the inside oroutside of any one of the side frames, or may be embedded in andintegrated with any one of the side frames.

The optical display unit 300 may be formed of a translucent material, sothat the optical display unit 300 can display images created by thecontrol unit 200 for recognition of the user 10 and can allow the userto view the external environment through the opening.

The optical display unit 300 may be inserted into and fixed to theopening contained in the front frame 110, or may be located at the rearsurface (interposed between the opening and the user 10) of the openingso that the optical display unit 300 may be fixed to the front frame110. For example, the optical display unit 300 may be located at therear surface of the opening, and may be fixed to the front frame 110 asan example.

Referring to the XR device shown in FIG. 23, when images are incidentupon an incident region S1 of the optical display unit 300 by thecontrol unit 200, image light may be transmitted to an emission regionS2 of the optical display unit 300 through the optical display unit 300,images created by the controller 200 can be displayed for recognition ofthe user 10.

Accordingly, the user 10 may view the external environment through theopening of the frame 100, and at the same time may view the imagescreated by the control unit 200.

FIG. 24 is a conceptual diagram illustrating a method for allowing an XRdevice to move a virtual object from one position to another positionaccording to the related art.

Referring to FIG. 24, the AR device acting as one example of the XRdevice may simultaneously display a real object 2410 present in the realworld and a virtual object 2420 on a display screen.

In this case, a conventional AR device according to the related art mayreact to a touch action of a user 2430, and may move the virtual object2420 only either in the X-axis directions 2421 and 2422 or in the Y-axisdirections 2423 and 2424.

Therefore, although the real object 2410 is actually in the 3Denvironment, the conventional XR device is unable to move the virtualobject 2420 in the Z-axis direction other than the X-axis and Y-axisdirections.

In contrast, the XR device according to the present disclosure canconsider not only the touch sensing result in the AR environment, butalso the result of sensing the user motion in the AR environment, suchthat the XR device can more efficiently control the position of avirtual object in three dimensions (3D). A detailed description thereofwill hereinafter be given with reference to FIGS. 25 to 38.

FIG. 25 is a conceptual diagram illustrating a method for allowing aplurality of cameras of the XR device to perform different functionsaccording to an embodiment of the present disclosure.

The XR device 2510 according to an embodiment of the present disclosuremay include at least two cameras.

The first camera located at the rear surface of the XR device 2510 maycapture an image of the real world. In contrast, the second cameralocated at the front surface of the XR device 2510 may be designed tocapture an image of the face 2531 of the user 2530. Therefore, the XRdevice may calculate the distance between the XR device 2510 and theface 2531 of the user 2530 using the second camera.

The second camera may be, for example, a depth camera, a ToF camera, orthe like. The second camera may estimate the distance between the userface 2531 and the XR device 2510 according to change in size of the userface 2531.

In FIG. 25, reference number 2520 may denote an enlarged view of thescreen of the XR device 2510.

In a situation in which a hand 2521 of the user touches the virtualobject 2540 displayed on the screen 2520 of the XR device, when thedistance between the XR device 2510 and the user face 2531 is changed,the depth value of the position of the virtual object 2540 may bechanged by the XR device.

For example, when the user face 2531 moves closer to the XR device in asituation in which the user hand 2521 touches the virtual object 2540,the virtual object 2510 may move in the (+)Z-axis direction. In otherwords, the XR device may display that the virtual object 2540 is locatedat a more distant position in the real-world environment. A detaileddescription thereof will be given later with reference to FIG. 32.

In contrast, when the user face 2531 moves farther from the XR device ina situation in which the user hand 2521 touches the virtual object 2540,the virtual object 2540 may move in the (−)Z-axis direction. In otherwords, the XR device may display that the virtual object 25440 islocated closer to the XR device in the real-word environment. A detaileddescription thereof will be given later with reference to FIG. 31.

FIG. 26 is a flowchart illustrating a method for controlling the XRdevice according to an embodiment of the present disclosure.

Referring to FIG. 26, the XR device provided with a plurality of camerasmay capture at least one real object located in the first directionusing a first camera from among the plurality of cameras (S2610). Asdescribed above, for example, the first camera may be located at therear surface of the XR device, and the first direction may refer to theother direction that does not face the user of the XR device.

The XR device may display not only at least one virtual object, but alsoat least one real object captured by the camera (S2620). For example,the virtual object displayed by the XR device may be changed based onthe captured real object. In more detail, when an image of a specificstore, for example, a store entitled “COFFEE BEAM”, is captured by thefirst camera, the XR device may display a virtual object (indicating theprice of coffee menus) related to the COFFEE BEAM store. In contrast,when the first camera captures an image of the sea, a virtual object(e.g., fishes) related to the sea may be displayed by the XR device.

Further, the XR device may recognize a first touch command through thescreen embedded therein (S2630).

In this case, the XR device may capture an image of the user who islocated in the second direction using the second camera from among theplurality of cameras, and may determine the presence or absence of achange in the distance between the user and the XR device (S2640).

If there is no change in the distance between the user and the XRdevice, the XR device may move the at least one virtual object to afirst position (hereinafter referred to as a first in-screen position)contained in the screen by reacting to the first touch command generatedin step S2630 (S2660). In this case, although only the position of thevirtual object is changed in step S2660, it should be noted that thereis no change in the size and depth of the virtual object in step S2660.

In contrast, if occurrence of the change in the size and depth of thevirtual object is decided, the XR device may move the at least onevirtual object to a second in-screen position by reacting not only tothe second touch command recognized through the XR-device screen, butalso to a motion (or gesture) of the user who is spaced apart from theXR device (S2650). Differently from step S2660, in step S2650, theposition of the virtual object is changed and the size and depth of thevirtual object are also changed.

The flowchart of the method shown in FIG. 26 can be applied to the XRdevice shown in FIG. 13, and a detailed description thereof willhereinafter be given.

The camera 1310 embedded in the XR device shown in FIG. 13 maycorrespond to a plurality of cameras.

The first camera may capture an image of at least one real objectlocated in the first direction, and the display 1320 may display atleast one virtual object and the at least one captured real object. Asdescribed above, for example, the virtual object to be displayed may bechanged based on the captured real object.

The processor 1340 (i.e., controller) may move the at least one virtualobject to the first in-screen position by reacting to the first touchcommand recognized through the XR-device screen. In this case, since thevirtual object is not changed in size, the 3D effect is not added tomovement of the virtual object.

The second camera may capture an image of the user who is located in thesecond direction. Whereas the first direction is directed to the realworld and the real object, each of which does not include the user, thesecond direction may refer to a direction directed to the user.

The processor 1340 may move the at least one virtual object to thesecond in-screen position by reacting not only to the second touchcommand recognized through the XR-device screen, but also the motion ofthe user who is spaced apart from the screen. Specifically, the XRdevice may be designed in a manner that the size of the virtual objectis changed, so that the 3D effect can be added to movement of thevirtual object.

Although not shown in FIG. 26, according to another embodiment of thepresent disclosure, in a situation in which the XR device does not moveonly by a predefined distance or less, the step S2640 may furtherinclude detecting the change in size in the user face captured by thesecond camera. Upon determining that the user face is reduced in size,the step S2640 may further include increasing the size of the virtualobject. Upon determining that the user face is enlarged in size, thestep S2640 may further include reducing the size of the virtual object.

Although not shown in FIG. 26, according to still another embodiment ofthe present disclosure, the step S2640 may further include determiningwhether the XR device has moved by the predefined distance or greaterusing the sensor embedded in the XR device. In contrast, when the XRdevice does not move by the predefined distance or greater, the stepS2640 may further include moving the at least one virtual object toanother position by reacting to the touch command and the user motion.In this case, the size of the moved virtual object may be changed. Inaddition, when the XR device has moved by the predefined distance orgreater, the step S2640 may further include moving the at least onevirtual object to another position by reacting to the touch command onlywithout reacting to the user motion. In this case, the size of thevirtual object is not changed. A detailed description thereof willhereinafter be given with reference to FIGS. 27 and 28.

As can be seen from FIG. 26, the position of the virtual object has beenmoved in the X-, Y-, and Y-axes in response to the distance between theuser (or the user face) and the XR device. However, in order to morecorrectly reflect the user intention into functions of the XR device, itis more preferable that not only the above method of FIG. 26 in whichthe change in distance between the user and the XR device is considered,but also another method for determining whether the XR device has movedto another position or has remained fixed only at one position beapplied to the XR device.

FIG. 27 is a conceptual diagram illustrating a method for allowing theXR device to distinguish movement of the user and movement of the XRdevice from each other according to an embodiment of the presentdisclosure.

As depicted in FIG. 27(a), it is assumed that the user 2710 and the XRdevice 2720 are spaced apart from each other by a predetermineddistance. As depicted in FIG. 27(b), in the situation in which the XRdevice 2721 moves from one position to another position 2730 and theposition of the user 2711 is fixed, the XR device does not adjust thedepth of the virtual object. This is because the user does not intend toadjust the depth of the virtual object, but desires to view anothervirtual object by moving the XR device to another position.

The other situation opposite to the situation of FIG. 27 willhereinafter be described with reference to FIG. 28.

FIG. 28 is a conceptual diagram illustrating a method for allowing theXR device to distinguish movement of the user from movement of the XRdevice according to another embodiment of the present disclosure.

As depicted in FIG. 28(a), it is assumed that the user 2810 and the XRdevice 2820 are spaced apart from each other by a predetermineddistance. As depicted in FIG. 28(b), when the XR device 2821 is fixedand the user 2811 moves to another position 2830, the depth of thevirtual object is adjusted. This is because the user does not intend toview another virtual object, but desires to adjust the depth of thevirtual object by moving the user face.

Meanwhile, information about whether the XR device shown in FIGS. 27 and28 has moved or not can be determined by the sensor 1330 of the XRdevice shown in FIG. 13. For example, the sensor 1330 may include a gyrosensor, a location sensor such as a GPS sensor, etc.

As described above, the conventional XR device can move the virtualobject only in the X-axis and Y-axis directions. This is because theconventional XR device can move the virtual object to another positionbased on the user touch action only. In contrast, the XR deviceaccording to the present disclosure can move the virtual object inthree-axes directions (i.e., X-axis, Y-axis, and Z-axis directions), andthe three-axes directions will hereinafter be described with referenceto FIG. 29.

FIG. 29 is a conceptual diagram illustrating examples of the X-axis, theY-axis, and the Z-axis according to the present disclosure.

Referring to FIG. 29, when viewed from the XR device 2910, the X-axisdirection may be formed based on a short side surface of the XR device,and the Y-axis direction may be formed based on a long side surface ofthe XR device. When viewed form the screen of the XR device 2910, thedirection perpendicular to the XR-device screen may be the Z-axisdirection. Alternatively, the Z-axis may be, for example, a line throughwhich the user who views the XR device is connected to the XR device.

The concepts shown in FIGS. 30 to 32 will hereinafter be described withreference to the X-axis, Y-axis, X-axis directions.

FIG. 30 is a conceptual diagram illustrating a situation in which the XRdevice simultaneously displays the real object and the virtual objectaccording to an embodiment of the present disclosure.

As depicted in FIG. 30(a), when the user 3010 who holds the XR device islocated in an arbitrary direction, the virtual object 3030 may bedisplayed. The enlarged view of the screen of the XR device 3020 shownin FIG. 30(a) may correspond to FIG. 30(b).

If the user who holds the XR device stands toward the arbitrarydirection, the XR device 3021 may display the virtual object 3031 on thescreen as shown in FIG. 30(b). In this case, the user may desire to movethe virtual object 3031 to be enlarged in size. In more detail, in orderfor the user to view the enlarged virtual object 3031, the virtualobject 3031 should move forward from the screen. However, theconventional XR device has disadvantages in that the virtual object canmove only in the X-axis, and Y-axis directions, so that it is impossiblefor the virtual object 3031 to move forward from the screen. In order toaddress the above issues, the present disclosure provides the followingmethod shown in FIG. 31.

FIG. 31 is a conceptual diagram illustrating a situation in which the XRdevice adjusts the depth of the virtual object in response to a firstmotion of the user.

As depicted in FIG. 31(a), when the user 3110 makes a first motion(e.g., a motion in which the user head moves backward from the screen,the XR device 3120 may detect that the distance between the user 3110and the XR device was relatively lengthened using the camera and thelike.

In this case, the virtual object 3130 displayed on the screen of the XRdevice 3120 may move forward from the screen so that the enlarged imageof the virtual object 3130 is displayed. For convenience of description,FIG. 31(b) illustrates the enlarged view of the XR device shown in FIG.31(a).

As described above, in a situation in which the XR device is fixed atone position, when the user head moves farther from the XR device, thevirtual object 3131 displayed in the screen of the XR device 3121 maymove in a forward direction from the screen as shown in FIG. 31(b). Thatis, in comparison between FIG. 30(b) and FIG. 31(b), the virtual object3131 shown in FIG. 31(b) is larger than the virtual object shown in FIG.30(b), so that the virtual object 3131 shown in FIG. 31(b) is theenlarged view of the virtual object shown FIG. 30(b). In more detail, ascompared to the virtual object of FIG. 30(b), the virtual object shownin FIG. 31(b) has a larger size and a smaller depth.

FIG. 32 is a conceptual diagram illustrating a situation in which the XRdevice adjusts the depth of the virtual object in response to a secondmotion of the user.

Referring to FIG. 32(a), when the user 3210 makes a second motion (e.g.,a motion in which the user head moves forward, the XR device may detectthat the distance between the XR device and the user 3210 was relativelyshortened using the camera and the like.

In this case, the virtual object 3230 displayed on the screen of the XRdevice may move backward from the screen (while being reduced in size).For convenience of description, FIG. 32(b) illustrates the enlarged viewof the XR device shown in FIG. 32(a).

As described above, in a situation in which the XR device is fixed atone position, when the user head moves closer to the XR device, thevirtual object 3231 displayed in the screen of the XR device 3221 maymove in a backward direction from the screen as shown in FIG. 32(b).That is, in comparison between FIG. 30(b) and FIG. 32(b), the virtualobject 3231 shown in FIG. 32(b) is smaller in display size than thevirtual object shown in FIG. 30(b), so that the virtual object 3231shown in FIG. 32(b) is a smaller-sized view of the virtual object shownFIG. 30(b). In more detail, as compared to the virtual object of FIG.30(b), the virtual object shown in FIG. 32(b) has a smaller size and ahigher depth.

The above-mentioned embodiments shown in the above drawings have assumedthat, in a situation in which the user touches a specific virtual objectdisplayed on the screen of the XR device, the position of the virtualobject can be changed in the 3D environment according to the changingdistance between the user face and the XR device. However, the XR devicetends to provide one or more virtual objects. Accordingly, the solutioncapable of easily changing the positions of the plurality of virtualobjects is also needed, and as such a detailed description thereof willhereinafter be given with reference to FIGS. 33 and 34.

FIG. 33 is a conceptual diagram illustrating a situation in which the XRdevice selects a plurality of virtual objects each having a depth to beadjusted.

As described above, the XR device according to the embodiment of thepresent disclosure includes at least two cameras. If the user touches asingle virtual object in the screen of the XR device, the XR device mayperform tracking of the gaze direction of the user using the secondcamera.

As depicted in FIG. 33(a), if it is determined that the tracked usergaze was directed to a specific virtual object touched by the touchcommand during a first reference time (1 second), a plurality of virtualobjects 3311 and 3312 located within the first radius 3310 from thecenter point of the specific virtual object may be grouped into a firstgroup.

In response to the touch command recognized through the screen of the XRdevice and the motion of the user who is spaced apart from the screen ofthe XR device, the plurality of virtual objects belonging to the firstgroup may move to other positions. That is, the depth values of thevirtual objects are changed, the plurality of virtual objects 3311 and3312 belonging to the first group may also be changed in size. As aresult, the user need not touch all the virtual objects.

Meanwhile, as depicted in FIG. 33(b), if it is determined that thetracked user gaze was directed to a specific virtual object touched bythe touch command during a second reference time (3 seconds), aplurality of virtual objects 3321, 3322, 3323, 3324, 3325, 3326, and3327 located within the second radius 3320 from the center point of thespecific virtual object may be grouped into a second group.

In response to the touch command recognized through the screen of the XRdevice and the motion of the user who is spaced apart from the screen ofthe XR device, the plurality of virtual objects belonging to the secondgroup may move to other positions. That is, the depth values of thevirtual objects are changed, the plurality of virtual objects 3321,3322, 3323, 3324, 3325, 3326, and 3327 belonging to the second group mayalso be changed in size. For example, when the user motion correspondsto the motion in which the user head moves closer to the XR device,whereas only the virtual object 3300 belonging to the second group movesin the backward direction from the screen as shown in FIG. 33(c), theother virtual objects 3331, 3332, 3333, and 3334 not belonging to thesecond group are not changed in depth at all.

Of course, FIG. 33 has disclosed the process for selecting many morevirtual objects according to the change in the user gaze time. However,when a predetermined situation in which the changed appearance (i.e.,the situation in which the user is opening their mouth) of the user'smouth is continuously maintained for a predetermined time is recognizedby the XR device through the cameras, the XR device according to thepresent disclosure may also be designed in a manner that the number ofvirtual objects to be selected can increase in proportion to theincreasing recognition time.

However, evolved technology for estimating such user intention moreperfectly than the example of FIG. 33 will hereinafter be described withreference to FIG. 34.

FIG. 34 is a conceptual diagram illustrating a database (DB) needed toadaptively group a plurality of virtual objects each having a depth tobe adjusted based on AI.

First, it is assumed that the database (DB) shown in FIG. 34(a) hasalready been stored in the memory for convenience of description. As thegaze time of the user who gazes at a specific object becomes longer, thenumber of virtual objects to be adjusted in depth can be changed. Aspreviously stated in FIG. 33, the length of the radius may be changedbased on a reference virtual object touched by the user. However, thepredetermined values shown in FIG. 34(a) need not be equally applied toall users.

Although not shown in FIG. 33, some user-undesired virtual objects notto be adjusted in depth may be contained in the plurality of virtualobjects belonging either to the first group or to the second group.Therefore, the XR device may display at least one option for cancellingsuch some virtual objects.

In this case, the XR device according to one embodiment of the presentdisclosure may calculate the distance between each of the cancelledvirtual objects and a specific virtual object (i.e., the center point)recognized by the touch command, and may update an initial radius valuestored in the memory by referring to the result of such calculation. Asdepicted in FIG. 34(b), the updated radius value may be stored in thememory.

Therefore, through the above-mentioned update process, the XR deviceaccording to the present disclosure can select many more virtual objectsduring the predefined section (e.g., 1 second corresponding to the usergaze maintenance time) in a manner that the radius becomes longer, orthe XR device can also select a smaller number of virtual objects duringthe predefined time section (e.g., 1 second corresponding to the usergaze maintenance time) in a manner that the radius becomes shorter.Moreover, through the above-mentioned update process, the dataprocessing rate can also be improved because the process for cancellingsome virtual objects contained in a specific group to perform depthadjustment can be omitted, resulting in higher technical effects.

As can be seen from the above-mentioned drawings, the above-mentionedembodiments have mainly disclosed various examples in which the positionof a target virtual object has been changed (e.g., change in depth,change in size, etc.) according to the distance between the user and theXR device. In contrast, another embodiment for rotating a target virtualobject according to the position of the user face will hereinafter bedescribed with reference to FIGS. 35 and 36.

FIGS. 35 and 36 are conceptual diagrams illustrating various situationsin which the XR device rotates the virtual object in response to changein the position of a user face.

In FIG. 35(a), it is assumed that the user 3510 is holding the XR device3520 in their hand. In this case, as can be seen from FIG. 35(b), it isalso assumed that, the user head (user face) 3511 moves in the X-axisdirection in a situation in which the user continuously touches aspecific virtual object.

In response to the above situation of FIG. 35(a), the specific virtualobject 3522 contained in the screen 3521 of the XR device may rotate inthe X-axis direction as shown in FIG. 35(c).

In FIG. 36, it is assumed that the user head (user face) turns in theother direction different from that of FIG. 35 for convenience ofdescription.

In FIG. 36(a), it is assumed that the user 3610 is holding the XR device3620 in their hand. In this case, as can be seen from FIG. 36(b), it isalso assumed that, the user head (user face) 3611 moves in the Y-axisdirection in a situation in which the user continuously touches aspecific virtual object.

Therefore, in response to the above situation of FIG. 36(a), thespecific virtual object 3622 contained in the screen 3621 of the XRdevice may rotate in the Y-axis direction as shown in FIG. 36(c).

The conventional device according to the related art has been designedto change the position of a virtual object only based on a touch actionof the user, and is unable to provide an interface for rotating thevirtual object.

Although the embodiments shown in the above-mentioned drawings havemainly disclosed only the XR device, another embodiment for allowing theabove-mentioned XR device to further control a robot through 5Gcommunication will hereinafter be described with reference to FIGS. 37and 38.

FIG. 37 is a flowchart illustrating a method for allowing the XR deviceto communicate with a robot according to an embodiment of the presentdisclosure.

As previously stated in the above-mentioned embodiments, the XR devicehas been designed to include a plurality of cameras.

The first camera may be located at the rear surface of the XR device,such that the first camera can capture only the real object other thanthe user. The XR device may determine whether at least one real objectcaptured by the first camera is a robot that is connected to the XRdevice through 5G communication or short range communication (S3710).

If the at least one real object captured by the first camera is therobot connected to the XR device through short range communication or 5Gcommunication, the XR device may create a specific virtual objectcorresponding to the robot (S3720).

Further, the XR device may display the created specific virtual object(e.g., a robot cleaner) on the screen.

Finally, the XR device may change the position of the specific virtualobject based on at least one of the touch command and the user motion(e.g., the motion in which the user head moves closer to the XR deviceor the motion in which the user head moves farther from the XR device(S3730).

Therefore, the present disclosure can allow the user who uses the XRdevice to easily move a target object such as the robot cleaner to ause-desired position, and as such a detailed description thereof willhereinafter be given with reference to FIG. 38.

FIG. 38 is a view illustrating a screen image acquired when the XRdevice displays a virtual object corresponding to the robot based on theconcept of FIG. 37.

Referring to FIG. 38, it is assumed that the XR device 3810 hasrecognized the presence of the robot corresponding to the real objectlocated in a peripheral region of the XR device 3810. Therefore, the XRdevice 3810 can display a virtual object 3811 corresponding to the realrobot cleaner.

In this case, the user may change a current position of the virtualobject 3811 to the other position, and may desire to move the real robotcleaner to the other position.

The conventional device according to the related art has been designedto move such a virtual object only within the 2D space, so that it isimpossible for the conventional device to move the robot cleaner to adistant position or a near position based on the reference position.

In contrast, the XR device according to the present disclosure can movethe virtual object 3811 corresponding to the robot cleaner even to aspecific point 3812 located behind a sofa or couch according to thechange in distance between the user and the XR device 3810.

As is apparent from the above description, the XR device according toone embodiment of the present disclosure can allow two cameras toperform different functions, such that 3D effects (e.g., with changingdepth values) can be allocated to an in-screen virtual object of the XRdevice.

The XR device according to another embodiment of the present disclosurecan provide a solution for allowing a plurality of virtual objects to besimultaneously selected within a minimum period of time.

The XR device according to still another embodiment of the presentdisclosure can analyze history information, and can thus adaptivelychange a grouping process needed for depth adjustment of the virtualobjects.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present disclosurewithout departing from the spirit or scope of the inventions. Thus, itis intended that the present disclosure covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method for controlling an extended reality (XR)device provided with a plurality of cameras, the method comprising:capturing at least one real object located in a first direction througha first camera; displaying at least one virtual object and the at leastone captured real object, wherein the displayed virtual object ischanged based on the captured real object; in response to a first touchcommand recognized through a screen of the XR device, moving the atleast one virtual object to a first position contained in the screen,wherein the virtual object remains unchanged in size; capturing a userwho is located in a second direction through a second camera, whereinthe first direction and the second direction are different from eachother; in response to a second touch command recognized through thescreen of the XR device and a motion of the user who is spaced apartfrom the screen of the XR device, moving the at least one virtual objectto a second position contained in the screen, wherein the virtual objectis changed in size; determining whether the XR device has moved by apredetermined range or greater by a sensor; if the XR device has notmoved by the predetermined range or greater, moving the at least onevirtual object to another position in response to the touch command andthe user motion, wherein the virtual object is changed in size; and ifthe XR has moved by the predetermined range or greater, moving the atleast one virtual object to the other position by reacting only to thetouch command without reacting to the user motion, wherein the virtualobject remains unchanged in size.
 2. The method according to claim 1,further comprising: if the XR device has not moved by the predeterminedrange or greater, detecting change in size of a facial image of the usercaptured by the second camera; if reduction in the user facial image isdetected, increasing the size of the virtual object; and if the enlargedfacial image of the user is detected, reducing the size of the virtualobject.
 3. The method according to claim 2, further comprising: trackinga gaze direction of the user using the second camera.
 4. The methodaccording to claim 3, further comprising: if the tracked user gaze isdirected to a specific virtual object touched by the second touchcommand during a first reference time period, grouping a plurality ofvirtual objects located in a first radius from a center point of thespecific virtual object into a first group; and in response to a secondtouch command recognized through the screen of the XR device and amotion of the user who is spaced apart from the screen of the XR device,moving the plurality of virtual objects belonging to the first group toother positions, wherein the virtual objects are changed in size.
 5. Themethod according to claim 4, further comprising: if the tracked usergaze is directed to a specific virtual object touched by the secondtouch command during a second reference time period, grouping aplurality of virtual objects located in a second radius from a centerpoint of the specific virtual object into a second group; and inresponse to a second touch command recognized through the screen of theXR device and a motion of the user who is spaced apart from the screenof the XR device, moving the plurality of virtual objects belonging tothe second group to other positions, wherein the virtual objects arechanged in size, wherein the second reference time period is longer thanthe first reference time period, and the second radius is longer thanthe first radius.
 6. The method according to claim 5, furthercomprising: displaying an option for cancelling some of the plurality ofvirtual objects belonging to the first group or the second group.
 7. Themethod according to claim 6, further comprising: calculating a distancebetween each of some cancelled virtual objects and a specific virtualobject touched by the second touch command; and updating a value of thefirst radius stored in a memory or a value of the second radius storedin the memory based on the calculation result.
 8. The method accordingto claim 7, further comprising: determining whether at least one realobject captured by the first camera is a robot connected through shortrange communication or 5G communication.
 9. The method according toclaim 8, further comprising: if the at least one real object captured bythe first camera is the robot connected through short rangecommunication or 5G communication, creating a specific virtual objectcorresponding to the robot; displaying the created specific virtualobject; and changing the position of the specific virtual object basedon at least one of the touch command and the user motion.
 10. Anextended reality (XR) device provided with a plurality of cameras, theXR device comprising: a first camera configured to capture at least onereal object located in a first direction; a display module configured todisplay at least one virtual object and the at least one captured realobject, wherein the displayed virtual object is changed based on thecaptured real object; a sensor configured to determine whether the XRdevice has moved by a predetermined range or greater; a controller, inresponse to a first touch command recognized through a screen of the XRdevice, configured to move the at least one virtual object to a firstposition contained in the screen, wherein the virtual object remainsunchanged in size; and a second camera configured to capture a user whois located in a second direction, wherein the first direction and thesecond direction are different from each other, wherein: the controller,in response to a second touch command recognized through the screen ofthe XR device and a motion of the user who is spaced apart from thescreen of the XR device, moves the at least one virtual object to asecond position contained in the screen, wherein the virtual object ischanged in size, if the XR device has not moved by the predeterminedrange or greater, the controller moves the at least one virtual objectto other position in response to the touch command and the user motion,and if the XR has moved by the predetermined range or greater, thecontroller moves the at least one virtual object to other position byreacting only to the touch command without reacting to the user motion.11. The XR device according to claim 10, wherein the controller: if theXR device has not moved by the predetermined range or greater, detectschange in size of a facial image of the user captured by the secondcamera; if reduction in the user facial image is detected, increases thesize of the virtual object; and if the enlarged facial image of the useris detected, reduces the size of the virtual object.
 12. The XR deviceaccording to claim 11, wherein the second camera is configured to tracka gaze direction of the user using the second camera.
 13. The XR deviceaccording to claim 12, wherein the controller: if the tracked user gazeis directed to a specific virtual object touched by the second touchcommand during a first reference time period, groups a plurality ofvirtual objects located in a first radius from a center point of thespecific virtual object into a first group; and in response to a secondtouch command recognized through the screen of the XR device and amotion of the user who is spaced apart from the screen of the XR device,moves the plurality of virtual objects belonging to the first group toother positions.
 14. The XR device according to claim 13, wherein thecontroller: if the tracked user gaze is directed to a specific virtualobject touched by the second touch command during a second referencetime period, groups a plurality of virtual objects located in a secondradius from a center point of the specific virtual object into a secondgroup; and in response to a second touch command recognized through thescreen of the XR device and a motion of the user who is spaced apartfrom the screen of the XR device, moves the plurality of virtual objectsbelonging to the second group to other positions, wherein the secondreference time period is longer than the first reference time period,and the second radius is longer than the first radius.
 15. The XR deviceaccording to claim 14, wherein the display module is configured todisplay an option for cancelling some of the plurality of virtualobjects belonging to the first group or the second group.
 16. The XRdevice according to claim 15, wherein the controller: calculates adistance between each of some cancelled virtual objects and a specificvirtual object touched by the second touch command; and updates a valueof the first radius stored in a memory or a value of the second radiusstored in the memory based on the calculation result.
 17. The XR deviceaccording to claim 16, wherein the controller is configured to determinewhether at least one real object captured by the first camera is a robotconnected through short range communication or 5G communication.
 18. TheXR device according to claim 17, wherein: the controller, if the atleast one real object captured by the first camera is the robotconnected through short range communication or 5G communication, createsa specific virtual object corresponding to the robot; and the displaymodule displays the created specific virtual object, and displays thespecific virtual object, a position of which is changed based on atleast one of the touch command and the user motion.